Regulatory Matters (Details) $ in Thousands	Jun. 30, 2020 USD ($)		Jun. 30, 2019 USD ($)
The Bank of Greene County [Member]
Compliance with Regulatory Capital [Abstract]
Total risk-based capital, actual amount	$ 142,524		$ 118,113
Total risk-based capital, actual ratio	0.160		0.158
Total risk-based capital for capital adequacy purposes, amount	$ 71,393		$ 59,842
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	$ 89,241		$ 74,802
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	0.0797		0.0779
Total risk-based capital for capital conservation buffer, required	0.0250		0.0250
Tier 1 risk-based capital, actual amount	$ 131,305		$ 108,716
Tier 1 risk-based capital, actual ratio	0.147		0.145
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 53,545		$ 44,881
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	$ 71,393		$ 59,842
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	0.0871		0.0853
Tier 1 risk-based capital for capital conservation buffer, required	2.50%		2.50%
Common equity tier 1 capital, actual amount	$ 131,305		$ 108,716
Common equity tier 1 capital, actual ratio	0.147		0.145
Common equity tier 1 capital for capital adequacy purposes, amount	$ 40,158		$ 33,661
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	$ 58,007		$ 48,621
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	0.1021		0.1003
Common equity tier 1 capital for capital conservation buffer, required	2.50%		2.50%
Tier 1 leverage ratio, actual amount	$ 131,305	[1]	$ 108,716
Tier 1 leverage ratio, actual ratio	0.081	[1]	0.087
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 65,238	[1]	$ 50,049
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	$ 81,547	[1]	$ 62,561
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	4.05%	[1]	4.68%
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	$ 60,832		$ 47,366
Total risk-based capital, actual ratio	0.453		0.474
Total risk-based capital for capital adequacy purposes, amount	$ 10,754		$ 7,996
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	$ 13,442		$ 9,996
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	0.3726		0.3939
Total risk-based capital for capital conservation buffer, required	0.0250		0.0250
Tier 1 risk-based capital, actual amount	$ 60,832		$ 47,366
Tier 1 risk-based capital, actual ratio	0.453		0.474
Tier 1 risk-based capital for capital adequacy purposes, amount	$ 8,065		$ 5,997
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	$ 10,754		$ 7,996
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	0.3926		0.4139
Tier 1 risk-based capital for capital conservation buffer, required	2.50%		2.50%
Common equity tier 1 capital, actual amount	$ 60,832		$ 47,366
Common equity tier 1 capital, actual ratio	0.453		0.474
Common equity tier 1 capital for capital adequacy purposes, amount	$ 6,049		$ 4,498
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	$ 8,737		$ 6,497
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	0.4076		0.4289
Common equity tier 1 capital for capital conservation buffer, required	2.50%		2.50%
Tier 1 leverage ratio, actual amount	$ 60,832		$ 47,366
Tier 1 leverage ratio, actual ratio	0.090		0.096
Tier 1 leverage ratio for capital adequacy purposes, amount	$ 26,976		$ 19,678
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	$ 33,720		$ 24,597
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	5.02%		5.63%
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.