Commitments and Contingent Liabilities (Details) - The Bank of Greene County [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Jun. 30, 2018
Commitments [Abstract]
Total commitments	$ 125,064	$ 95,487
Unfunded Loan Commitments [Member]
Commitments [Abstract]
Total commitments	55,874	36,624
Unused Lines of Credit [Member]
Commitments [Abstract]
Total commitments	$ 69,190	$ 58,863