Loans and Allowance - Information pertaining to principal balances and specific reserve allocations for impaired loans (Details 6) (Loans Receivable, USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	$ 10,025	$ 10,161
Impaired loans without a specific allowance, unpaid principal balance	10,986	11,914
Impaired loans with a specific allowance, recorded Investment	5,599	4,067
Impaired loans with a specific allowance, unpaid principal balance	5,655	4,086
Impaired loans with a related allowance, specific allowance	1,106	794
Total impaired loans, recorded investment	15,624	14,228
Total impaired loans, unpaid principal balance	16,641	16,000
Total impaired loans, specific allowance	1,106	794
Construction / Land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	2,653	2,870
Impaired loans without a specific allowance, unpaid principal balance	2,842	3,379
Impaired loans with a specific allowance, recorded Investment	1,877	1,882
Impaired loans with a specific allowance, unpaid principal balance	1,891	1,882
Impaired loans with a related allowance, specific allowance	196	195
Total impaired loans, recorded investment	4,530	4,752
Total impaired loans, unpaid principal balance	4,733	5,261
Total impaired loans, specific allowance	196	195
1-4 family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	3,897	3,562
Impaired loans without a specific allowance, unpaid principal balance	3,969	3,612
Impaired loans with a specific allowance, recorded Investment	1,594	955
Impaired loans with a specific allowance, unpaid principal balance	1,612	957
Impaired loans with a related allowance, specific allowance	526	310
Total impaired loans, recorded investment	5,491	4,517
Total impaired loans, unpaid principal balance	5,581	4,569
Total impaired loans, specific allowance	526	310
Multi-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	52	53
Impaired loans without a specific allowance, unpaid principal balance	54	54
Impaired loans with a specific allowance, recorded Investment	1,036	1,051
Impaired loans with a specific allowance, unpaid principal balance	1,052	1,061
Impaired loans with a related allowance, specific allowance	196	196
Total impaired loans, recorded investment	1,088	1,104
Total impaired loans, unpaid principal balance	1,106	1,115
Total impaired loans, specific allowance	196	196
Nonresidential and agricultural land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	3,213	3,278
Impaired loans without a specific allowance, unpaid principal balance	3,740	4,439
Impaired loans with a specific allowance, recorded Investment	914
Impaired loans with a specific allowance, unpaid principal balance	914
Impaired loans with a related allowance, specific allowance	97
Total impaired loans, recorded investment	4,127	3,278
Total impaired loans, unpaid principal balance	4,654	4,439
Total impaired loans, specific allowance	97
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	199	386
Impaired loans without a specific allowance, unpaid principal balance	370	418
Impaired loans with a specific allowance, recorded Investment	178	179
Impaired loans with a specific allowance, unpaid principal balance	186	186
Impaired loans with a related allowance, specific allowance	91	93
Total impaired loans, recorded investment	377	565
Total impaired loans, unpaid principal balance	556	604
Total impaired loans, specific allowance	91	93
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	11	12
Impaired loans without a specific allowance, unpaid principal balance	11	12
Impaired loans with a specific allowance, recorded Investment
Impaired loans with a specific allowance, unpaid principal balance
Impaired loans with a related allowance, specific allowance
Total impaired loans, recorded investment	11	12
Total impaired loans, unpaid principal balance	11	12
Total impaired loans, specific allowance