Fair Value Measurements - Estimate of the Fair Value of Financial Instruments Not Recorded at Fair Value on Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financial Assets:
State tax credits held for sale	$ 19,822	$ 23,020
Fair Value, Level 1
Financial Assets:
Portfolio loans, net	0	0
State tax credits held for sale	0	0
Financial Liabilities:
Deposits	1,811,549	2,079,141
Subordinated debentures	0	0
Federal Home Loan Bank advances	0	0
Other borrowings	0	0
Fair Value, Level 2
Financial Assets:
Portfolio loans, net	0	0
State tax credits held for sale	0	0
Financial Liabilities:
Deposits	0	0
Subordinated debentures	63,867	65,840
Federal Home Loan Bank advances	198,587	89,301
Other borrowings	189,391	245,224
Fair Value, Level 3
Financial Assets:
Portfolio loans, net	2,209,475	2,266,834
State tax credits held for sale	40,002	43,802
Financial Liabilities:
Deposits	562,988	589,972
Subordinated debentures	0	0
Federal Home Loan Bank advances	0	0
Other borrowings	0	0
Estimated fair value
Financial Assets:
Portfolio loans, net	2,209,475	2,266,834
State tax credits held for sale	40,002	43,802
Financial Liabilities:
Deposits	2,374,537	2,669,113
Subordinated debentures	63,867	65,840
Federal Home Loan Bank advances	198,587	89,301
Other borrowings	$ 189,391	$ 245,224