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Segment disclosures

Company overview

CHEMUNG FINANCIAL CORPORATION

Each reported dimension combination stays separate. Revenue and operating income are shown as reported, with their dates and sources.

Revenue · Reported segment facts

120 dimension combinations 800 retained observations 23 reported periods Partial retained history

Counts describe retained dimensioned rows only. Periods and members can change across reports, and this view does not infer missing values or expected segment totals.

Intersegment Elimination · Interchange Revenue · Holding Company And CFS

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence

Intersegment Elimination · Interchange Revenue · Holding Company CFS And CRM

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2024-01-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence

Intersegment Elimination · Investment Brokerage · Holding Company And CFS

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-31477000 USD20260507Open filing evidence
2025-07-01 – 2025-09-30300000 USD20251106Open filing evidence
2025-01-01 – 2025-09-30793000 USD20251106Open filing evidence
2025-04-01 – 2025-06-30270000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-30493000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-31223000 USD20260507Open filing evidence
2024-07-01 – 2024-09-30306000 USD20251106Open filing evidence
2024-01-01 – 2024-09-30787000 USD20251106Open filing evidence
2024-04-01 – 2024-06-30253000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-30481000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-31228000 USD2025-05-07 · 14:46:57.000ZOpen filing evidence

Intersegment Elimination · Investment Brokerage · Holding Company CFS And CRM

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-311176000 USD20260313Open filing evidence
2024-01-01 – 2024-12-311054000 USD20260313Open filing evidence
2024-07-01 – 2024-09-30306000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2024-01-01 – 2024-09-30787000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-12-31995000 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-30243000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-30749000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2022-07-01 – 2022-09-30251000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-30775000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-30346000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-30796000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Intersegment Elimination · Overdraft Fees · Holding Company And CFS

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence

Intersegment Elimination · Overdraft Fees · Holding Company CFS And CRM

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2024-01-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Intersegment Elimination · Overdraft Fees · Holding Company CFS And CRM Member

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Intersegment Elimination · Service Chargeon Deposits Other · Holding Company And CFS

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence

Intersegment Elimination · Service Chargeon Deposits Other · Holding Company CFS And CRM

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2024-01-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence

Intersegment Elimination · Service Chargeon Deposits Other · Holding Company CFS And CRM Member

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Intersegment Elimination · WMG Fee Income · Holding Company And CFS

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence

Intersegment Elimination · WMG Fee Income · Holding Company CFS And CRM

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2024-01-01 – 2024-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Intersegment Elimination · Holding Company CFS And CRM · Investment Brokerage

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-03-31241000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-31253000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence

Intersegment Elimination · Holding Company CFS And CRM · Service Chargeon Deposits Other

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Intersegment Elimination · Holding Company CFS And CRM Member · Interchange Revenue

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Intersegment Elimination · Holding Company CFS And CRM Member · Service Chargeon Deposits Other

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Intersegment Elimination · Holding Company CFS And CRM Member · WMG Fee Income

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Operating Segments · Interchange Revenue · Core Banking Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-311014000 USD20260507Open filing evidence
2025-01-01 – 2025-12-314302000 USD20260313Open filing evidence
2025-07-01 – 2025-09-301073000 USD20251106Open filing evidence
2025-01-01 – 2025-09-303220000 USD20251106Open filing evidence
2025-04-01 – 2025-06-301110000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-302147000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-311037000 USD20260507Open filing evidence
2024-01-01 – 2024-12-314426000 USD20260313Open filing evidence
2024-07-01 – 2024-09-301123000 USD20251106Open filing evidence
2024-01-01 – 2024-09-303327000 USD20251106Open filing evidence
2024-04-01 – 2024-06-301141000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-302204000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-311063000 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-01-01 – 2023-12-314606000 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-301141000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-303468000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-03-311133000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-311130000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-301237000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-303622000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence

Operating Segments · Interchange Revenue · Wealth Management Group Services Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence

Operating Segments · Interchange Revenue · WMG

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence

Operating Segments · Investment Brokerage · Core Banking Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2021-05-12 · 19:17:31.000ZOpen filing evidence

Operating Segments · Investment Brokerage · Wealth Management Group Services Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence

Operating Segments · Investment Brokerage · WMG

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence

Operating Segments · Overdraft Fees · Core Banking Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-31679000 USD20260507Open filing evidence
2025-01-01 – 2025-12-312862000 USD20260313Open filing evidence
2025-07-01 – 2025-09-30699000 USD20251106Open filing evidence
2025-01-01 – 2025-09-302149000 USD20251106Open filing evidence
2025-04-01 – 2025-06-30719000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-301450000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-31731000 USD20260507Open filing evidence
2024-01-01 – 2024-12-312997000 USD20260313Open filing evidence
2024-07-01 – 2024-09-30768000 USD20251106Open filing evidence
2024-01-01 – 2024-09-302196000 USD20251106Open filing evidence
2024-04-01 – 2024-06-30718000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-301428000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-31710000 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-01-01 – 2023-12-313096000 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-30817000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-302308000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2022-01-01 – 2022-12-313084000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2022-04-01 – 2022-06-30727000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-301400000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-31673000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-12-312266000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-07-01 – 2021-09-30623000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-301561000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-04-01 – 2021-06-30489000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-30938000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-31450000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Operating Segments · Overdraft Fees · Wealth Management Group Services Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence

Operating Segments · Overdraft Fees · WMG

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence

Operating Segments · Service Chargeon Deposits Other · Core Banking Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-31372000 USD20260507Open filing evidence
2025-01-01 – 2025-12-311565000 USD20260313Open filing evidence
2025-07-01 – 2025-09-30395000 USD20251106Open filing evidence
2025-01-01 – 2025-09-301179000 USD20251106Open filing evidence
2025-04-01 – 2025-06-30395000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-30784000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-31389000 USD20260507Open filing evidence
2024-01-01 – 2024-12-311045000 USD20260313Open filing evidence
2024-07-01 – 2024-09-30248000 USD20251106Open filing evidence
2024-01-01 – 2024-09-30733000 USD20251106Open filing evidence
2024-04-01 – 2024-06-30246000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-30485000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-31239000 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-01-01 – 2023-12-31823000 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-30201000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-30610000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-04-01 – 2023-06-30182000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-30409000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2022-04-01 – 2022-06-30209000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-30400000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-04-01 – 2021-06-30243000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-30511000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-31267000 USD2021-05-12 · 19:17:31.000ZOpen filing evidence

Operating Segments · Service Chargeon Deposits Other · Wealth Management Group Services Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Operating Segments · Service Chargeon Deposits Other · WMG

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence

Operating Segments · WMG Fee Income · Core Banking Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-310 USD20260507Open filing evidence
2025-01-01 – 2025-12-310 USD20260313Open filing evidence
2025-07-01 – 2025-09-300 USD20251106Open filing evidence
2025-01-01 – 2025-09-300 USD20251106Open filing evidence
2025-04-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-310 USD20260507Open filing evidence
2024-01-01 – 2024-12-310 USD20260313Open filing evidence
2024-07-01 – 2024-09-300 USD20251106Open filing evidence
2024-01-01 – 2024-09-300 USD20251106Open filing evidence
2024-04-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-01-01 – 2023-12-310 USD2025-03-14 · 20:04:14.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Operating Segments · WMG Fee Income · Wealth Management Group Services Segment

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2026-01-01 – 2026-03-313145000 USD20260507Open filing evidence
2025-07-01 – 2025-09-302967000 USD20251106Open filing evidence
2025-01-01 – 2025-09-308827000 USD20251106Open filing evidence
2025-04-01 – 2025-06-302993000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-06-305860000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2025-01-01 – 2025-03-312867000 USD20260507Open filing evidence
2024-07-01 – 2024-09-302991000 USD20251106Open filing evidence
2024-01-01 – 2024-09-308554000 USD20251106Open filing evidence
2024-04-01 – 2024-06-302860000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-06-305563000 USD2025-08-07 · 16:13:10.000ZOpen filing evidence
2024-01-01 – 2024-03-312703000 USD2025-05-07 · 14:46:57.000ZOpen filing evidence
2023-07-01 – 2023-09-302533000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2023-01-01 – 2023-09-307716000 USD2024-11-07 · 15:49:08.000ZOpen filing evidence
2022-04-01 – 2022-06-302628000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-305385000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-07-01 – 2021-09-302765000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-308246000 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-04-01 – 2021-06-302803000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-305481000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Operating Segments · WMG Fee Income · WMG

Consolidation Items · Product Or Service · Statement Business Segments

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2025-01-01 – 2025-12-3111945000 USD20260313Open filing evidence
2024-01-01 – 2024-12-3111573000 USD20260313Open filing evidence
2023-01-01 – 2023-12-3110460000 USD2025-03-14 · 20:04:14.000ZOpen filing evidence

Operating Segments · Core Banking Segment · Interchange Revenue

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-311063000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-01-01 – 2023-03-311133000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-01-01 – 2022-12-314603000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2022-01-01 – 2022-03-311130000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-12-314844000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-03-311123000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Operating Segments · Core Banking Segment · Investment Brokerage

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Operating Segments · Core Banking Segment · Overdraft Fees

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-30817000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-302308000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-03-31714000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-07-01 – 2022-09-30846000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-302246000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-31673000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence

Operating Segments · Core Banking Segment · Service Chargeon Deposits Other

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-31239000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-07-01 – 2023-09-30201000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-30610000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-03-31227000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-01-01 – 2022-12-31704000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2022-07-01 – 2022-09-30143000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-30543000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-31191000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-01-01 – 2021-12-31948000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-07-01 – 2021-09-30233000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-30744000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-03-31267000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Operating Segments · Core Banking Segment · WMG Fee Income

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2021-05-12 · 19:17:31.000ZOpen filing evidence

Operating Segments · Wealth Management Group Services Segment · Interchange Revenue

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence

Operating Segments · Wealth Management Group Services Segment · Investment Brokerage

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Operating Segments · Wealth Management Group Services Segment · Overdraft Fees

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Operating Segments · Wealth Management Group Services Segment · Service Chargeon Deposits Other

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2021-11-10 · 18:53:22.000ZOpen filing evidence

Operating Segments · Wealth Management Group Services Segment · WMG Fee Income

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-03-312580000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence
2022-01-01 – 2022-03-312757000 USD2023-05-12 · 20:28:09.000ZOpen filing evidence

Operating Segments · WMG · Interchange Revenue

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Operating Segments · WMG · Investment Brokerage

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Operating Segments · WMG · Overdraft Fees

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Operating Segments · WMG · Service Chargeon Deposits Other

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Operating Segments · WMG · WMG Fee Income

Consolidation Items · Statement Business Segments · Product Or Service

Source dimensions srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-3110280000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-3111072000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Interchange Revenue · Intersegment Elimination · Holding Company CFS And CRM

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Interchange Revenue · Intersegment Elimination · Holding Company CFS And CRM Member

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Interchange Revenue · Operating Segments · Core Banking Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-301141000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-302204000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-07-01 – 2023-09-301141000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-303468000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-04-01 – 2023-06-301194000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-302327000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2022-07-01 – 2022-09-301126000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-303462000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-301206000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-302336000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-07-01 – 2021-09-301237000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-303622000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-04-01 – 2021-06-301262000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-302385000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Interchange Revenue · Operating Segments · Wealth Management Group Services Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Interchange Revenue · Core Banking Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-301107000 USD20260806Open filing evidence
2026-01-01 – 2026-06-302121000 USD20260806Open filing evidence
2025-04-01 – 2025-06-301110000 USD20260806Open filing evidence
2025-01-01 – 2025-06-302147000 USD20260806Open filing evidence
2023-01-01 – 2023-12-314606000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2023-04-01 – 2023-06-301194000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-302327000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-12-314603000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-04-01 – 2022-06-301206000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-302336000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-01-01 – 2021-12-314844000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-314068000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Interchange Revenue · Holding Company And CFS · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence

Interchange Revenue · Holding Company CFS And CRM · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence

Interchange Revenue · Holding Company CFS And CRM Member

Product Or Service · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2020-01-01 – 2020-12-310 USD2021-03-24 · 20:21:42.000ZOpen filing evidence

Interchange Revenue · Wealth Management Group Services Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence

Interchange Revenue · WMG

Product Or Service · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2020-01-01 – 2020-12-310 USD2021-03-24 · 20:21:42.000ZOpen filing evidence

Interchange Revenue · WMG · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Investment Brokerage · Intersegment Elimination · Holding Company CFS And CRM

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-30253000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-30481000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-30265000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-30506000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence

Investment Brokerage · Intersegment Elimination · Holding Company CFS And CRM Member

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-31995000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-311079000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2021-01-01 – 2021-12-311043000 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Investment Brokerage · Operating Segments · Core Banking Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Investment Brokerage · Operating Segments · Wealth Management Group Services Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Investment Brokerage · Core Banking Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Investment Brokerage · Holding Company And CFS · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-30394000 USD20260806Open filing evidence
2026-01-01 – 2026-06-30871000 USD20260806Open filing evidence
2025-04-01 – 2025-06-30270000 USD20260806Open filing evidence
2025-01-01 – 2025-06-30493000 USD20260806Open filing evidence

Investment Brokerage · Holding Company CFS And CRM Member · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-311043000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-31657000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Investment Brokerage · Wealth Management Group Services Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Investment Brokerage · WMG · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Overdraft Fees · Intersegment Elimination · Holding Company CFS And CRM

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence

Overdraft Fees · Intersegment Elimination · Holding Company CFS And CRM Member

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

Overdraft Fees · Operating Segments · Core Banking Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-30718000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-301428000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-03-31710000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-04-01 – 2023-06-30777000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-301491000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-03-31714000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-30846000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-302246000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-30623000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-301561000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Overdraft Fees · Operating Segments · Wealth Management Group Services Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

Overdraft Fees · Core Banking Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-30674000 USD20260806Open filing evidence
2026-01-01 – 2026-06-301353000 USD20260806Open filing evidence
2025-04-01 – 2025-06-30719000 USD20260806Open filing evidence
2025-01-01 – 2025-06-301450000 USD20260806Open filing evidence
2023-01-01 – 2023-12-313096000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-313084000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Overdraft Fees · Holding Company And CFS · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence

Overdraft Fees · Holding Company CFS And CRM · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Overdraft Fees · Wealth Management Group Services Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence

Overdraft Fees · WMG

Product Or Service · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember
PeriodValueUnitFiledEvidence
2020-01-01 – 2020-12-310 USD2021-03-24 · 20:21:42.000ZOpen filing evidence

Overdraft Fees · WMG · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Service Chargeon Deposits Other · Intersegment Elimination · Holding Company CFS And CRM

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence

Service Chargeon Deposits Other · Core Banking Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-30364000 USD20260806Open filing evidence
2026-01-01 – 2026-06-30736000 USD20260806Open filing evidence
2025-04-01 – 2025-06-30395000 USD20260806Open filing evidence
2025-01-01 – 2025-06-30784000 USD20260806Open filing evidence
2023-01-01 – 2023-12-31823000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-31704000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

Service Chargeon Deposits Other · Holding Company And CFS · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence

Service Chargeon Deposits Other · Holding Company CFS And CRM · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Service Chargeon Deposits Other · Wealth Management Group Services Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Service Chargeon Deposits Other · WMG · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2020-01-01 – 2020-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

WMG Fee Income · Intersegment Elimination · Holding Company CFS And CRM

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence

WMG Fee Income · Intersegment Elimination · Holding Company CFS And CRM Member

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence
2021-01-01 – 2021-12-310 USD2023-03-22 · 19:09:34.000ZOpen filing evidence

WMG Fee Income · Operating Segments · Core Banking Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-300 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

WMG Fee Income · Operating Segments · Wealth Management Group Services Segment

Product Or Service · Consolidation Items · Statement Business Segments

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember
PeriodValueUnitFiledEvidence
2024-04-01 – 2024-06-302860000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-06-305563000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2024-01-01 – 2024-03-312703000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-04-01 – 2023-06-302603000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-06-305183000 USD2024-08-07 · 14:22:40.000ZOpen filing evidence
2023-01-01 – 2023-03-312580000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-302403000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2022-01-01 – 2022-09-307788000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-07-01 – 2021-09-302765000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence
2021-01-01 – 2021-09-308246000 USD2022-11-09 · 21:43:54.000ZOpen filing evidence

WMG Fee Income · Core Banking Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

WMG Fee Income · Holding Company And CFS · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyAndCFSMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-300 USD20260806Open filing evidence
2026-01-01 – 2026-06-300 USD20260806Open filing evidence
2025-04-01 – 2025-06-300 USD20260806Open filing evidence
2025-01-01 – 2025-06-300 USD20260806Open filing evidence

WMG Fee Income · Holding Company CFS And CRM · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

WMG Fee Income · Holding Company CFS And CRM Member · Intersegment Elimination

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

WMG Fee Income · Wealth Management Group Services Segment · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2026-04-01 – 2026-06-303191000 USD20260806Open filing evidence
2026-01-01 – 2026-06-306336000 USD20260806Open filing evidence
2025-04-01 – 2025-06-302993000 USD20260806Open filing evidence
2025-01-01 – 2025-06-305860000 USD20260806Open filing evidence
2021-04-01 – 2021-06-302803000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-305481000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

WMG Fee Income · WMG · Operating Segments

Product Or Service · Statement Business Segments · Consolidation Items

Source dimensions srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-3111072000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Core Banking Segment · Operating Segments · Interchange Revenue

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2021-04-01 – 2021-06-301262000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-302385000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Core Banking Segment · Operating Segments · Overdraft Fees

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember
PeriodValueUnitFiledEvidence
2021-04-01 – 2021-06-30489000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-30938000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Core Banking Segment · Investment Brokerage · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Core Banking Segment · Overdraft Fees · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-30777000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-301491000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-30727000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-301400000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-01-01 – 2021-12-312266000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Core Banking Segment · Service Chargeon Deposits Other · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-30182000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-30409000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-30209000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-30400000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-01-01 – 2021-12-31948000 USD2022-03-23 · 18:15:09.000ZOpen filing evidence
2021-04-01 – 2021-06-30243000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-30511000 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Core Banking Segment · WMG Fee Income · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:CoreBankingSegmentMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence

Holding Company CFS And CRM · Intersegment Elimination · Interchange Revenue

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence

Holding Company CFS And CRM · Intersegment Elimination · Service Chargeon Deposits Other

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence

Holding Company CFS And CRM · Interchange Revenue · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2022-04-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Holding Company CFS And CRM · Investment Brokerage · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-31228000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-07-01 – 2023-09-30243000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-30749000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-04-01 – 2023-06-30265000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-30506000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-03-31241000 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-30251000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-30775000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-30271000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-30524000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-03-31253000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-04-01 – 2021-06-30236000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-30450000 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-03-31214000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Holding Company CFS And CRM · Overdraft Fees · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Holding Company CFS And CRM · Service Chargeon Deposits Other · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Holding Company CFS And CRM · WMG Fee Income · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2024-01-01 – 2024-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-03-310 USD2024-05-08 · 15:57:54.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2022-08-11 · 18:59:18.000ZOpen filing evidence

Holding Company CFS And CRM Member · Interchange Revenue · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Holding Company CFS And CRM Member · Overdraft Fees · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Holding Company CFS And CRM Member · Service Chargeon Deposits Other · Intersegment Elimination

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:HoldingCompanyCFSAndCRMMemberMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:IntersegmentEliminationMember
PeriodValueUnitFiledEvidence
2021-01-01 – 2021-12-310 USD2022-03-23 · 18:15:09.000ZOpen filing evidence

Wealth Management Group Services Segment · Operating Segments · Interchange Revenue

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember
PeriodValueUnitFiledEvidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Wealth Management Group Services Segment · Operating Segments · Investment Brokerage

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:InvestmentBrokerageMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Wealth Management Group Services Segment · Operating Segments · Overdraft Fees

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-04-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-06-300 USD2021-08-12 · 17:47:28.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Wealth Management Group Services Segment · Operating Segments · Service Chargeon Deposits Other

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-310 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Wealth Management Group Services Segment · Operating Segments · WMG Fee Income

Statement Business Segments · Consolidation Items · Product Or Service

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-302533000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-307716000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-07-01 – 2022-09-302403000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-307788000 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-03-312757000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence
2021-01-01 – 2021-03-312678000 USD2022-05-12 · 18:16:21.000ZOpen filing evidence

Wealth Management Group Services Segment · Interchange Revenue · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:InterchangeRevenueMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-07-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2023-01-01 – 2023-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-07-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence
2022-01-01 – 2022-09-300 USD2023-11-09 · 17:52:04.000ZOpen filing evidence

Wealth Management Group Services Segment · Overdraft Fees · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:OverdraftFeesMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence

Wealth Management Group Services Segment · Service Chargeon Deposits Other · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-300 USD2023-08-10 · 16:14:25.000ZOpen filing evidence

Wealth Management Group Services Segment · WMG Fee Income · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WealthManagementGroupServicesSegmentMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-04-01 – 2023-06-302603000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2023-01-01 – 2023-06-305183000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-04-01 – 2022-06-302628000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence
2022-01-01 – 2022-06-305385000 USD2023-08-10 · 16:14:25.000ZOpen filing evidence

WMG · Service Chargeon Deposits Other · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:ServiceChargeonDepositsOtherMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-310 USD2024-03-13 · 20:14:56.000ZOpen filing evidence

WMG · WMG Fee Income · Operating Segments

Statement Business Segments · Product Or Service · Consolidation Items

Source dimensions us-gaap:StatementBusinessSegmentsAxis=chmg:WMGMember;srt:ProductOrServiceAxis=chmg:WMGFeeIncomeMember;srt:ConsolidationItemsAxis=us-gaap:OperatingSegmentsMember
PeriodValueUnitFiledEvidence
2023-01-01 – 2023-12-3110460000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence
2022-01-01 – 2022-12-3110280000 USD2024-03-13 · 20:14:56.000ZOpen filing evidence