Loans and Allowance for Loan Losses - Nonaccrual and Past Due Loans (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012 Loans	Dec. 31, 2011 Loans
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	$ 57,053	$ 70,354
Ratio of nonperforming loans to all loans	4.12%	4.78%
Total number of loans on nonaccrual status	441	505
Past due Loans, Aging Analysis
30 to 59 Days Past Due	9,486	21,009
60 to 89 Days Past Due	11,938	4,879
Greater Than 90 Days	24,019	30,866
Total Past Due	45,443	56,754
Current	1,312,197	1,393,285
Loans	1,357,640	1,450,039
Real Estate Loans | Construction Loans
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	16,497	26,575
Past due Loans, Aging Analysis
30 to 59 Days Past Due	706	2,265
60 to 89 Days Past Due	2,258	402
Greater Than 90 Days	8,223	15,538
Total Past Due	11,187	18,205
Current	136,221	184,598
Loans	147,408	202,803
Real Estate Loans | Owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	14,771	16,339
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,414	4,342
60 to 89 Days Past Due	1,883	1,215
Greater Than 90 Days	3,727	3,727
Total Past Due	7,024	9,284
Current	339,884	339,647
Loans	346,908	348,931
Real Estate Loans | Non-owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	5,936	7,634
Past due Loans, Aging Analysis
30 to 59 Days Past Due	2,686	9,723
60 to 89 Days Past Due	2,178	86
Greater Than 90 Days	3,141	4,679
Total Past Due	8,005	14,488
Current	222,849	228,339
Loans	230,854	242,827
Real Estate Loans | One to Four Family
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	6,370	7,271
Past due Loans, Aging Analysis
30 to 59 Days Past Due	2,286	3,441
60 to 89 Days Past Due	1,534	1,049
Greater Than 90 Days	3,406	2,955
Total Past Due	7,226	7,445
Current	167,486	171,602
Loans	174,712	179,047
Real Estate Loans | Multifamily
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	713	942
Past due Loans, Aging Analysis
30 to 59 Days Past Due	6	277
60 to 89 Days Past Due	79	0
Greater Than 90 Days	0	896
Total Past Due	85	1,173
Current	37,902	38,708
Loans	37,987	39,881
Real Estate Loans | Home Equity Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	3,950	2,222
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,345	0
60 to 89 Days Past Due	216	634
Greater Than 90 Days	2,209	856
Total Past Due	3,770	1,490
Current	192,719	199,730
Loans	196,489	201,220
Commercial
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	8,293	8,896
Past due Loans, Aging Analysis
30 to 59 Days Past Due	767	586
60 to 89 Days Past Due	3,678	1,432
Greater Than 90 Days	3,055	2,087
Total Past Due	7,500	4,105
Current	161,010	172,942
Loans	168,510	177,047
Consumer and other
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	523	475
Past due Loans, Aging Analysis
30 to 59 Days Past Due	276	375
60 to 89 Days Past Due	112	61
Greater Than 90 Days	258	128
Total Past Due	646	564
Current	54,126	57,719
Loans	$ 54,772	$ 58,283