XML 83 R71.htm IDEA: XBRL DOCUMENT v3.25.1

BORROWED FUNDS - Corporation's Borrowed Funds Outstanding (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Federal Home Loan Bank, Advance, Branch of FHLBank [Line Items]
FHLBNY term advances, balance	$ 85,000	$ 109,110
Fixed rate advance
Federal Home Loan Bank, Advance, Branch of FHLBank [Line Items]
FHLBNY term advances, balance	$ 55,000
FHLBNY term advances, rate	4.49%
Fixed rate advance
Federal Home Loan Bank, Advance, Branch of FHLBank [Line Items]
FHLBNY term advances, balance	$ 30,000
FHLBNY term advances, rate	4.48%
FHLBNY overnight advances
Federal Home Loan Bank, Advance, Branch of FHLBank [Line Items]
FHLBNY term advances, balance		$ 109,110
FHLBNY term advances, rate		4.69%

X

- Definition

Amount of advance from Federal Home Loan Bank (FHLBank).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478878/942-470-45-1

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Rate of interest applicable on advance from Federal Home Loan Bank (FHLBank).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 470
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478878/942-470-45-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=chmg_FHLBNYTermAdvancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=chmg_FHLBNYTermAdvancesTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=chmg_FHLBNYOvernightAdvancesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: