XML 50 R38.htm IDEA: XBRL DOCUMENT v3.24.3

Summary of Significant Accounting Policies, Nature of Operations (Details)	Sep. 30, 2024 Office
Nature of Operations [Abstract]
Number of offices	18

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