Regulatory Capital - Bank's actual and required capital amounts and ratios (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Regulatory Capital [Abstract]
Total risk-based capital (to risk-weighted assets), actual, amount	$ 42,665	$ 40,015
Total risk-based capital (to risk-weighted assets), actual, ratio	13.70%	14.68%
Total risk-based capital (to risk-weighted assets), required for adequate capital, amount	24,918	21,804
Total risk-based capital (to risk-weighted assets), required for adequate capital, ratio	8.00%	8.00%
Total risk-based capital (to risk-weighted assets), to be well capitalized, amount	31,147	27,256
Total risk-based capital (to risk-weighted assets), to be well capitalized, ratio	10.00%	10.00%
Tier I capital (to risk-weighted assets), actual, amount	39,101	37,449
Tier I capital (to risk-weighted assets), actual, ratio	12.55%	13.74%
Tier I capital (to risk-weighted assets), required for adequate capital, amount	12,459	10,902
Tier I capital (to risk-weighted assets), required for adequate capital, ratio	4.00%	4.00%
Tier I capital (to risk-weighted assets), to be well capitalized, amount	18,688	16,353
Tier I capital (to risk-weighted assets), to be well capitalized, ratio	6.00%	6.00%
Tier I capital (to average assets), actual amount	39,101	37,449
Tier I capital (to average assets), actual, ratio	8.29%	9.25%
Tier I capital (to average assets), required for adequate capital, amount	18,871	16,197
Tier I capital (to average assets), required for adequate capital, ratio	4.00%	4.00%
Tier I capital (to average assets), to be well capitalized, amount	23,589	20,246
Tier I capital (to average assets), to be well capitalized, ratio	5.00%	5.00%
Tangible capital (to adjusted total assets), actual, amount		37,449
Tangible capital (to adjusted total assets), actual, ratio		9.25%
Tangible capital (to adjusted total assets), required for adequate capital, amount		$ 6,074
Tangible capital (to adjusted total assets), required for adequate capital, ratio		1.50%