Regulatory Matters (Details) $ in Thousands	Jun. 30, 2021 USD ($)		Jun. 30, 2020 USD ($)
The Bank of Greene County [Member]
Compliance with Regulatory Capital [Abstract]
Total risk-based capital, actual amount	$ 184,063		$ 142,524
Total risk-based capital, actual ratio	0.169		0.160
Total risk-based capital for capital adequacy purposes, amount	$ 87,384		$ 71,393
Total risk-based capital for capital adequacy purposes, ratio	0.080		0.080
Total risk-based capital to be well capitalized under prompt corrective action provisions, amount	$ 109,230		$ 89,241
Total risk-based capital to be well capitalized under prompt corrective action provisions, ratio	0.100		0.100
Total risk-based capital for capital conservation buffer, actual	0.0885		0.0797
Total risk-based capital for capital conservation buffer, required	0.0250		0.0250
Tier 1 risk-based capital, actual amount	$ 170,335		$ 131,305
Tier 1 risk-based capital, actual ratio	0.156		0.147
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 65,538		$ 53,545
Tier 1 risk-based capital for capital adequacy purposes, ratio	0.060		0.060
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions, amount	$ 87,384		$ 71,393
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions, ratio	0.080		0.080
Tier 1 risk-based capital for capital conservation buffer, actual	0.0959		0.0871
Tier 1 risk-based capital for capital conservation buffer, required	2.50%		2.50%
Common equity tier 1 capital, actual amount	$ 170,335		$ 131,305
Common equity tier 1 capital, actual ratio	0.156		0.147
Common equity tier 1 capital for capital adequacy purposes, amount	$ 49,154		$ 40,158
Common equity tier 1 capital for capital adequacy purposes, ratio	0.045		0.045
Common equity tier 1 capital to be well capitalized under prompt corrective action provisions, amount	$ 71,000		$ 58,007
Common equity tier 1 capital to be well capitalized under prompt corrective action provisions, ratio	0.065		0.065
Common equity tier 1 capital for capital conservation buffer, actual	0.1109		0.1021
Common equity tier 1 capital for capital conservation buffer, required	2.50%		2.50%
Tier 1 leverage ratio, actual amount	$ 170,335	[1]	$ 131,305
Tier 1 leverage ratio, actual ratio	0.080	[1]	0.081
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 85,382	[1]	$ 65,238
Tier 1 leverage ratio for capital adequacy purposes, ratio	0.040	[1]	0.040
Tier 1 leverage ratio to be well capitalized under prompt corrective action provisions, amount	$ 106,728	[1]	$ 81,547
Tier 1 leverage ratio to be well capitalized under prompt corrective action provisions, ratio	0.050	[1]	0.050
Tier 1 leverage ratio for capital conservation buffer, actual	3.98%	[1]	4.05%
Tier 1 leverage ratio for capital conservation buffer, required	2.50%	[1]	2.50%
Greene County Commercial Bank [Member]
Compliance with Regulatory Capital [Abstract]
Total risk-based capital, actual amount	$ 68,116		$ 60,832
Total risk-based capital, actual ratio	0.402		0.453
Total risk-based capital for capital adequacy purposes, amount	$ 13,566		$ 10,754
Total risk-based capital for capital adequacy purposes, ratio	0.080		0.080
Total risk-based capital to be well capitalized under prompt corrective action provisions, amount	$ 16,958		$ 13,442
Total risk-based capital to be well capitalized under prompt corrective action provisions, ratio	0.100		0.100
Total risk-based capital for capital conservation buffer, actual	0.3217		0.3726
Total risk-based capital for capital conservation buffer, required	0.0250		0.0250
Tier 1 risk-based capital, actual amount	$ 68,116		$ 60,832
Tier 1 risk-based capital, actual ratio	0.402		0.453
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 10,175		$ 8,065
Tier 1 risk-based capital for capital adequacy purposes, ratio	0.060		0.060
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions, amount	$ 13,566		$ 10,754
Tier 1 risk-based capital to be well capitalized under prompt corrective action provisions, ratio	0.080		0.080
Tier 1 risk-based capital for capital conservation buffer, actual	0.3417		0.3926
Tier 1 risk-based capital for capital conservation buffer, required	2.50%		2.50%
Common equity tier 1 capital, actual amount	$ 68,116		$ 60,832
Common equity tier 1 capital, actual ratio	0.402		0.453
Common equity tier 1 capital for capital adequacy purposes, amount	$ 7,631		$ 6,049
Common equity tier 1 capital for capital adequacy purposes, ratio	0.045		0.045
Common equity tier 1 capital to be well capitalized under prompt corrective action provisions, amount	$ 11,023		$ 8,737
Common equity tier 1 capital to be well capitalized under prompt corrective action provisions, ratio	0.065		0.065
Common equity tier 1 capital for capital conservation buffer, actual	0.3567		0.4076
Common equity tier 1 capital for capital conservation buffer, required	2.50%		2.50%
Tier 1 leverage ratio, actual amount	$ 68,116		$ 60,832
Tier 1 leverage ratio, actual ratio	0.079		0.090
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 34,412		$ 26,976
Tier 1 leverage ratio for capital adequacy purposes, ratio	0.040		0.040
Tier 1 leverage ratio to be well capitalized under prompt corrective action provisions, amount	$ 43,015		$ 33,720
Tier 1 leverage ratio to be well capitalized under prompt corrective action provisions, ratio	0.050		0.050
Tier 1 leverage ratio for capital conservation buffer, actual	3.92%		5.02%
Tier 1 leverage ratio for capital conservation buffer, required	2.50%		2.50%

[1] Average assets have been adjusted for PPPLF borrowings in calculation of Tier 1 Leverage Ratio.