XML 75 R63.htm IDEA: XBRL DOCUMENT v3.25.1

LEASES - Leased Branch Properties (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Leases [Abstract]
Operating lease right-of-use assets	$ 5,446	$ 5,648
Less: accumulated amortization	(194)	(772)
Less: lease termination	0	0
Add: lease modifications	80	570
Operating lease right-of-use assets	$ 5,332	$ 5,446

X

- Definition

Operating Lease, Right-Of-Use Asset, Accumulated Amortization

+ References

No definition available.

+ Details

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Namespace Prefix:	chmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Operating Lease, Right-Of-Use Asset, Gross

+ References

No definition available.

+ Details

Name:	chmg_OperatingLeaseRightOfUseAssetGross
Namespace Prefix:	chmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Operating Lease, Right-of-Use Asset, Lease Termination

+ References

No definition available.

+ Details

Name:	chmg_OperatingLeaseRightOfUseAssetLeaseTermination
Namespace Prefix:	chmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Operating Lease, Right-of-Use Asset, New Lease Agreement and Modifications

+ References

No definition available.

+ Details

Name:	chmg_OperatingLeaseRightOfUseAssetNewLeaseAgreementAndModifications
Namespace Prefix:	chmg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

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

X

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant