Loans and Allowance - Information pertaining to principal balances and specific reserve allocations for impaired loans, as well as average balances of and interest recognized on impaired loans (Details 6) (Loans Receivable, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	$ 10,161	$ 11,352
Impaired loans without a specific allowance, unpaid principal balance	11,914	12,330
Impaired loans without a specific allowance, average investment	11,929	13,377
Impaired loans without a specific allowance, interest income recognized	249	433
Impaired loans with a specific allowance, recorded Investment	4,067	5,910
Impaired loans with a specific allowance, unpaid principal balance	4,086	5,910
Impaired loans with a related allowance, specific allowance	794	1,432
Impaired loans with a related allowance, average investment	3,749	5,668
Impaired loans with a related allowance, interest income recognized	14	100
Total impaired loans, recorded investment	14,228	17,262
Total impaired loans, unpaid principal balance	16,000	18,240
Total impaired loans, specific allowance	794	1,432
Total impaired loans, average investment	15,678	19,045
Total impaired loans, interest income recognized	263	533
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	398
Impaired loans without a specific allowance, unpaid principal balance	400
Impaired loans without a specific allowance, average investment	158	159
Impaired loans without a specific allowance, interest income recognized	2	1
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
Impaired loans with a related allowance, average investment
Impaired loans with a related allowance, interest income recognized
Total impaired loans, recorded investment	398
Total impaired loans, unpaid principal balance	400
Total impaired loans, specific allowance
Total impaired loans, average investment	158	159
Total impaired loans, interest income recognized	2	1
1-4 family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	3,562	3,064
Impaired loans without a specific allowance, unpaid principal balance	3,612	3,249
Impaired loans without a specific allowance, average investment	5,003	2,722
Impaired loans without a specific allowance, interest income recognized	157	153
Impaired loans with a specific allowance, recorded Investment	955	3,267
Impaired loans with a specific allowance, unpaid principal balance	957	3,267
Impaired loans with a related allowance, specific allowance	310	913
Impaired loans with a related allowance, average investment	950	3,232
Impaired loans with a related allowance, interest income recognized	10	58
Total impaired loans, recorded investment	4,517	6,331
Total impaired loans, unpaid principal balance	4,569	6,516
Total impaired loans, specific allowance	310	913
Total impaired loans, average investment	5,953	5,954
Total impaired loans, interest income recognized	167	211
Multi-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	53	1,966
Impaired loans without a specific allowance, unpaid principal balance	54	1,966
Impaired loans without a specific allowance, average investment	41	2,052
Impaired loans without a specific allowance, interest income recognized	2	77
Impaired loans with a specific allowance, recorded Investment	1,051
Impaired loans with a specific allowance, unpaid principal balance	1,061
Impaired loans with a related allowance, specific allowance	196
Impaired loans with a related allowance, average investment	804
Impaired loans with a related allowance, interest income recognized	4
Total impaired loans, recorded investment	1,104	1,966
Total impaired loans, unpaid principal balance	1,115	1,966
Total impaired loans, specific allowance	196
Total impaired loans, average investment	845	2,052
Total impaired loans, interest income recognized	6	77
Nonresidential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	3,278	3,705
Impaired loans without a specific allowance, unpaid principal balance	4,439	4,469
Impaired loans without a specific allowance, average investment	3,692	4,324
Impaired loans without a specific allowance, interest income recognized	70	143
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
Impaired loans with a related allowance, average investment
Impaired loans with a related allowance, interest income recognized
Total impaired loans, recorded investment	3,278	3,705
Total impaired loans, unpaid principal balance	4,439	4,469
Total impaired loans, specific allowance
Total impaired loans, average investment	3,692	4,324
Total impaired loans, interest income recognized	70	143
Land
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	2,472	2,329
Impaired loans without a specific allowance, unpaid principal balance	2,979	2,329
Impaired loans without a specific allowance, average investment	2,598	3,635
Impaired loans without a specific allowance, interest income recognized		44
Impaired loans with a specific allowance, recorded Investment	1,882	2,643
Impaired loans with a specific allowance, unpaid principal balance	1,882	2,643
Impaired loans with a related allowance, specific allowance	195	519
Impaired loans with a related allowance, average investment	1,903	2,436
Impaired loans with a related allowance, interest income recognized		42
Total impaired loans, recorded investment	4,354	4,972
Total impaired loans, unpaid principal balance	4,861	4,972
Total impaired loans, specific allowance	195	519
Total impaired loans, average investment	4,501	6,071
Total impaired loans, interest income recognized		86
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	386	271
Impaired loans without a specific allowance, unpaid principal balance	418	300
Impaired loans without a specific allowance, average investment	423	476
Impaired loans without a specific allowance, interest income recognized	17	15
Impaired loans with a specific allowance, recorded Investment	179
Impaired loans with a specific allowance, unpaid principal balance	186
Impaired loans with a related allowance, specific allowance	93
Impaired loans with a related allowance, average investment	92
Impaired loans with a related allowance, interest income recognized
Total impaired loans, recorded investment	565	271
Total impaired loans, unpaid principal balance	604	300
Total impaired loans, specific allowance	93
Total impaired loans, average investment	515	476
Total impaired loans, interest income recognized	17	15
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans without a specific allowance, recorded investment	12	17
Impaired loans without a specific allowance, unpaid principal balance	12	17
Impaired loans without a specific allowance, average investment	14	9
Impaired loans without a specific allowance, interest income recognized	1
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
Impaired loans with a related allowance, average investment
Impaired loans with a related allowance, interest income recognized
Total impaired loans, recorded investment	12	17
Total impaired loans, unpaid principal balance	12	17
Total impaired loans, specific allowance
Total impaired loans, average investment	14	9
Total impaired loans, interest income recognized	$ 1