Condensed Financial Statements of Greene County Bancorp, Inc., Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
OPERATING EXPENSES [Abstract]
Other	$ 2,045	$ 1,754
Net income	7,189	6,528
Parent Company [Member]
INCOME [Abstract]
Equity in undistributed net income of subsidiaries	7,491	4,682
Dividend distributed by subsidiary	4	2,004
Interest-earning deposits	5	7
Total income	7,500	6,693
OPERATING EXPENSES [Abstract]
Legal Fees	201	62
Other	110	103
Total operating expenses	311	165
Net income	$ 7,189	$ 6,528