Condensed Financial Statements of Greene County Bancorp, Inc., Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
INCOME [Abstract]
Other Income	$ 997	$ 1,123
OPERATING EXPENSES [Abstract]
Interest on borrowings	1,963	962
Other expense	3,330	2,820
Net income	27,986	23,942
Parent Company [Member]
INCOME [Abstract]
Equity in undistributed net income of subsidiaries	28,155	20,362
Dividend distributed by subsidiary	2,004	4,834
Interest-earning deposits	1	5
Other Income	11	0
Total Income	30,171	25,201
OPERATING EXPENSES [Abstract]
Legal fees	65	78
Interest on borrowings	1,688	820
Other expense	432	361
Total operating expenses	2,185	1,259
Net income	$ 27,986	$ 23,942