Regulatory Matters (Details)	Jun. 30, 2026	Jun. 30, 2025
Greene County Bancorp, Inc. [Member]
Regulatory Matters [Abstract]
Common equity tier 1 capital for capital conservation buffer, required	2.50%	2.50%
The Bank of Greene County [Member]
Regulatory Matters [Abstract]
Common equity tier 1 capital for capital conservation buffer, required	2.50%	2.50%
Greene County Commercial Bank [Member]
Regulatory Matters [Abstract]
Common equity tier 1 capital for capital conservation buffer, required	2.50%	2.50%

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

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