Loans and Allowance for Loan Losses - Nonaccrual and Past Due Loans (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013 Loans	Dec. 31, 2012 Loans
Financing Receivable, Recorded Investment, Past Due
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 0	$ 0
Financing receivables on nonaccrual status	19,698	22,817
Loans and Leases Receivable, Ratio of Nonperforming Loans to All Loans	1.47%	1.71%
Total number of loans on nonaccrual status	195	315
Past due Loans, Aging Analysis
30 to 59 Days Past Due	6,438	13,943
60 to 89 Days Past Due	2,057	2,000
Greater Than 90 Days	8,905	13,362
Total Past Due	17,400	29,305
Current	1,296,347	1,279,067
Loans	1,313,747	1,308,372
Real Estate Loans | Construction Loans
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	4,098	7,385
Past due Loans, Aging Analysis
30 to 59 Days Past Due	831	4,395
60 to 89 Days Past Due	392	345
Greater Than 90 Days	1,399	1,865
Total Past Due	2,622	6,605
Current	124,942	125,376
Loans	127,564	131,981
Real Estate Loans | Owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	5,141	5,787
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,140	838
60 to 89 Days Past Due	74	114
Greater Than 90 Days	2,989	4,237
Total Past Due	4,203	5,189
Current	358,604	337,773
Loans	362,807	342,962
Real Estate Loans | Non-owner Occupied
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,337	1,697
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,822	1,688
60 to 89 Days Past Due	24	500
Greater Than 90 Days	570	1,098
Total Past Due	2,416	3,286
Current	205,720	208,203
Loans	208,136	211,489
Real Estate Loans | One to Four Family
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,749	3,123
Past due Loans, Aging Analysis
30 to 59 Days Past Due	429	2,767
60 to 89 Days Past Due	1,344	910
Greater Than 90 Days	1,172	2,226
Total Past Due	2,945	5,903
Current	164,838	162,708
Loans	167,783	168,611
Real Estate Loans | Multifamily
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	261	539
Past due Loans, Aging Analysis
30 to 59 Days Past Due	0	12
60 to 89 Days Past Due	0	0
Greater Than 90 Days	0	10
Total Past Due	0	22
Current	33,724	35,315
Loans	33,724	35,337
Real Estate Loans | Home Equity Lines of Credit
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,003	1,041
Past due Loans, Aging Analysis
30 to 59 Days Past Due	1,593	1,980
60 to 89 Days Past Due	50	52
Greater Than 90 Days	60	924
Total Past Due	1,703	2,956
Current	193,945	188,932
Loans	195,648	191,888
Commercial
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	2,743	2,790
Past due Loans, Aging Analysis
30 to 59 Days Past Due	487	2,027
60 to 89 Days Past Due	130	34
Greater Than 90 Days	2,612	2,660
Total Past Due	3,229	4,721
Current	165,127	169,719
Loans	168,356	174,440
Consumer and other
Financing Receivable, Recorded Investment, Past Due
Financing receivables on nonaccrual status	366	455
Past due Loans, Aging Analysis
30 to 59 Days Past Due	136	236
60 to 89 Days Past Due	43	45
Greater Than 90 Days	103	342
Total Past Due	282	623
Current	49,447	51,041
Loans	$ 49,729	$ 51,664