Fair Value (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011
Financial liabilities:
Federal funds purchased and securities sold under agreements to repurchase	$ 226,330	$ 180,436	$ 184,403
Other borrowings	45,807	46,683	46,955
Fair Value
Financial assets:
Cash and cash equivalents	278,064	171,425
Investment securities	501,769	325,351
Loans, net of allowance for loan losses, and loans held for sale	3,077,060	2,859,513
FDIC receivable for loss share agreements	104,231	202,313
Accrued interest receivable	10,487	11,527
Financial liabilities:
Deposits	3,525,346	3,222,547
Federal funds purchased and securities sold under agreements to repurchase	226,330	180,436
Other borrowings	47,826	48,915
Accrued interest payable	1,921	2,254
Interest rate swap - cash flow hedge	1,579	1,391
Fair Value | Commitments to extend credit
Financial liabilities:
Off balance sheet financial instruments	9,715	7,657
Level 1
Financial assets:
Cash and cash equivalents	278,064	171,425
Investment securities	8,344	18,593
Level 2
Financial assets:
Investment securities	493,425	306,758
Loans, net of allowance for loan losses, and loans held for sale	71,585	45,809
Accrued interest receivable	10,487	11,527
Financial liabilities:
Deposits	3,525,346	3,222,547
Federal funds purchased and securities sold under agreements to repurchase	226,330	180,436
Other borrowings	47,826	48,915
Accrued interest payable	1,921	2,254
Interest rate swap - cash flow hedge	1,579	1,391
Level 2 | Commitments to extend credit
Financial liabilities:
Off balance sheet financial instruments	9,715	7,657
Level 3
Financial assets:
Loans, net of allowance for loan losses, and loans held for sale	3,005,475	2,813,704
FDIC receivable for loss share agreements	104,231	202,313
Carrying Amount
Financial assets:
Cash and cash equivalents	278,064	171,425
Investment securities	500,587	324,056
Loans, net of allowance for loan losses, and loans held for sale	3,032,351	2,837,588
FDIC receivable for loss share agreements	174,321	262,651
Accrued interest receivable	10,487	11,527
Financial liabilities:
Deposits	3,589,298	3,254,472
Federal funds purchased and securities sold under agreements to repurchase	226,330	180,436
Other borrowings	45,807	46,683
Accrued interest payable	1,921	2,254
Interest rate swap - cash flow hedge	$ 1,579	$ 1,391