Commitments and Contingent Liabilities (Details) - The Bank of Greene County [Member] - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019
Commitments [Abstract]
Total commitments	$ 170,574	$ 125,064
Unfunded Loan Commitments [Member]
Commitments [Abstract]
Total commitments	100,241	55,874
Unused Lines of Credit [Member]
Commitments [Abstract]
Total commitments	$ 70,333	$ 69,190