Fair Value Measurements (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financial assets:
Cash and due from banks	$ 447,608	$ 351,255
Loans, net	1,982,074	1,985,095
Financial liabilities:
Junior subordinated debt owed to unconsolidated trusts	55,000	55,000
Carrying Amount | Level 2 Inputs
Financial assets:
Cash and due from banks	447,608	351,255
Loans held for sale	30,833	40,003
Accrued interest receivable	12,795	12,275
Financial liabilities:
Deposits	3,016,945	2,980,292
Securities sold under agreements to repurchase	130,809	139,024
Long-term debt	6,000	7,000
Junior subordinated debt owed to unconsolidated trusts	55,000	55,000
Accrued interest payable	963	1,128
Carrying Amount | Level 3 Inputs
Financial assets:
Loans, net	1,982,074	1,985,095
Fair Value | Level 2 Inputs
Financial assets:
Cash and due from banks	447,608	351,255
Loans held for sale	31,463	40,971
Accrued interest receivable	12,795	12,275
Financial liabilities:
Deposits	3,022,715	2,987,524
Securities sold under agreements to repurchase	130,809	139,024
Long-term debt	6,042	7,120
Junior subordinated debt owed to unconsolidated trusts	55,000	55,000
Accrued interest payable	963	1,128
Fair Value | Level 3 Inputs
Financial assets:
Loans, net	$ 1,998,039	$ 2,006,588