Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Cash and cash equivalents, Carrying Amount	$ 240,307	$ 141,088	$ 219,806	$ 235,962
Investment securities, Carrying Amount	308,721	341,935
Loans, net, Carrying Amount	623,373	675,376
Accrued interest receivable, Carrying Amount	5,117	6,276
Assets, Carrying Amount	1,177,518	1,164,675
Cash and cash equivalents, Fair Value	240,307	141,088
Loans, net, Fair Value	629,106	676,675
Investment securities, Fair Value	308,721	341,935
Accrued interest receivable, Fair Value	5,117	6,276
Assets, Fair Value	1,183,251	1,165,974
Deposits	560,836	563,708
Accounts and drafts payable	564,731	522,761
Accrued interest payable, Carrying Amount	109	112
Liabilities, Carrying Amount	1,125,676	1,086,581
Deposits, Fair Value	561,217	564,189
Accounts and drafts payable, Fair Value	564,731	522,761
Accrued interest payable, Fair Value	109	112
Liabilities, Fair Value	$ 1,126,057	$ 1,087,062