Regulatory Matters (Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Jun. 30, 2012
The Bank of Greene County [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Amount	$ 58,892	$ 52,000
Total capital (to risk weighted assets) For Capital Adequacy Purposes, Amount	25,424	23,506
Total capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	31,780	29,383
Total capital (to risk weighted assets), Ratio	18.50%	17.70%
Total capital (to risk weighted assets) For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Total capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 capital (to risk weighted assets), Amount	54,843	48,287
Tier 1 capital (to risk weighted assets) For Capital Adequacy Purposes, Amount	12,712	11,753
Tier 1 capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	19,068	17,630
Tier 1 capital (to risk weighted assets), Ratio	17.30%	16.40%
Tier 1 capital (to risk weighted assets) For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 capital (to average assets), Amount	54,843	48,287
Tier 1 capital (to average assets) For Capital Adequacy Purposes, Amount	19,050	17,733
Tier 1 capital (to average assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	31,751	29,555
Tier 1 capital (to average assets), Ratio	8.60%	8.20%
Tier 1 capital (to average assets) For Capital Adequacy Purposes, Ratio	3.00%	3.00%
Tier 1 capital (to average assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%
Greene County Commercial Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total capital (to risk weighted assets), Amount	15,256	13,237
Total capital (to risk weighted assets) For Capital Adequacy Purposes, Amount	3,091	2,677
Total capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	3,864	3,346
Total capital (to risk weighted assets), Ratio	39.50%	39.60%
Total capital (to risk weighted assets) For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Total capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 capital (to risk weighted assets), Amount	15,256	13,237
Tier 1 capital (to risk weighted assets) For Capital Adequacy Purposes, Amount	1,546	1,338
Tier 1 capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	2,318	2,008
Tier 1 capital (to risk weighted assets), Ratio	39.50%	39.60%
Tier 1 capital (to risk weighted assets) For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 capital (to risk weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 capital (to average assets), Amount	15,256	13,237
Tier 1 capital (to average assets) For Capital Adequacy Purposes, Amount	7,912	6,903
Tier 1 capital (to average assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 9,890	$ 8,629
Tier 1 capital (to average assets), Ratio	7.70%	7.70%
Tier 1 capital (to average assets) For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 capital (to average assets) To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%