XML 45 R34.htm IDEA: XBRL DOCUMENT v3.22.0.1

Nature of Operations (Details)	Dec. 31, 2021 Office
Nature of Operations [Abstract]
Number of full-service offices	17

X

- References

No definition available.

+ Details

Name:	gcbc_NatureOfOperationsAbstract
Namespace Prefix:	gcbc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Represents the number of stores.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStores
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant