Fair Value of Financial Instruments (Summary of Carrying Amounts and Estimated Fair Values of Selected Financial Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Cash and due from banks	$ 97,432	$ 55,492
Interest-earning deposits with banks	250,030	458,638
Securities available for sale	995,854	763,866
FHLB stock	22,215	17,908
Loans	2,778,282	2,371,822
FDIC loss-sharing asset	193,869	205,991
Deposits	3,795,499	3,327,269
FHLB Advances	122,642	119,405
Repurchase agreements	25,000	25,000
Other borrowings	0	642
Long-term subordinated debt	0	25,735
Carrying Amount [Member]
Cash and due from banks	97,432	55,492
Interest-earning deposits with banks	250,030	458,638
Securities available for sale	995,854	763,866
FHLB stock	22,215	17,908
Loans held for sale	2,568	754
Loans	2,778,282	2,371,822
FDIC loss-sharing asset	193,869	205,991
Interest rate contracts	16,463	10,167
Deposits	3,795,499	3,327,269
FHLB Advances	122,642	119,405
Repurchase agreements	25,000	25,000
Other borrowings	0	642
Long-term subordinated debt	0	25,735
Interest rate contracts	16,463	10,167
Fair Value [Member]
Cash and due from banks	97,432	55,492
Interest-earning deposits with banks	250,030	458,638
Securities available for sale	995,854	763,866
FHLB stock	22,215	17,908
Loans held for sale	2,568	754
Loans	3,039,531	2,525,113
FDIC loss-sharing asset	193,869	205,991
Interest rate contracts	16,463	10,167
Deposits	3,797,901	3,330,616
FHLB Advances	124,358	122,722
Repurchase agreements	27,022	27,251
Other borrowings	0	642
Long-term subordinated debt	0	20,156
Interest rate contracts	$ 16,463	$ 10,167