Consolidated Statements of Changes in Shareholders' Equity (Parenthetical)		12 Months Ended
Mar. 15, 2016 $ / shares shares	Jun. 30, 2016 $ / shares
Additional stock issued, stock split (in shares) \| shares	4,305,670
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Stock split ratio	2	2
Dividends per share (in dollars per share)		$ 0.37
Greene County Bancorp, MHC [Member]
Ownership percentage by parent company		54.40%

Aggregate dividends declared during the period for each share of common stock outstanding.

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