Condensed Financial Statements of Greene County Bancorp, Inc. - Condensed Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net Income	$ 6,528	$ 6,371
Adjustments to reconcile net income to cash provided by (used by) operating activities:
Tax benefit of stock based compensation	(27)	0
Net increase in prepaid expenses and other assets	88	(1,096)
Net cash provided by operating activities	11,385	10,335
Cash flows from financing activities
Payment of cash dividends	(1,335)	(2,128)
Excess tax benefit from share-based payment arrangements	27	0
Net cash provided by financing activities	33,049	38,098
Net increase (decrease) in cash and cash equivalents	7,587	(1,520)
Parent Company [Member]
Cash flows from operating activities:
Net Income	6,528	6,371
Adjustments to reconcile net income to cash provided by (used by) operating activities:
Undistributed earnings of subsidiaries	(4,682)	(6,501)
Tax benefit of stock based compensation	(28)	0
Net increase in prepaid expenses and other assets	0	(2)
Net increase in total liabilities	20	3
Net cash provided by operating activities	1,838	(129)
Cash flows from financing activities
Payment of cash dividends	(1,335)	(2,128)
Proceeds from exercise of stock options	172	124
Excess tax benefit from share-based payment arrangements	28	0
Net cash provided by financing activities	(1,135)	(2,004)
Net increase (decrease) in cash and cash equivalents	703	(2,133)
Cash and cash equivalents at beginning of period	2,114	4,247
Cash and cash equivalents at end of period	$ 2,817	$ 2,114