Fair Value Accounting and Measurement Fair Value Accounting and Measurement (Carrying Amounts and Estimated Fair Values of Selected Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets
Interest-earning deposits with banks	$ 14,531	$ 389,353
Securities available for sale	1,664,111	1,001,665
Reported Value Measurement [Member]
Assets
Cash and due from banks	165,030	124,573
Interest-earning deposits with banks	14,531	389,353
Securities available for sale	1,664,111	1,001,665
FHLB stock	32,529	21,819
Loans held for sale	735	2,563
Loans	4,444,842	2,864,803
FDIC loss-sharing asset	39,846	96,354
Interest rate contracts	9,044	14,921
Liabilities
Deposits	5,959,475	4,042,085
FHLB Advances	36,606	6,644
Repurchase agreements	25,000	25,000
Interest rate contracts	9,044	14,921
Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	165,030	124,573
Interest-earning deposits with banks	14,531	389,353
Securities available for sale	1,664,111	1,001,665
FHLB stock	32,529	21,819
Loans held for sale	735	2,563
Loans	4,605,038	2,944,317
FDIC loss-sharing asset	11,248	26,543
Interest rate contracts	9,044	14,921
Liabilities
Deposits	5,958,747	4,043,221
FHLB Advances	35,080	5,894
Repurchase agreements	26,361	26,464
Interest rate contracts	9,044	14,921
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Securities available for sale	1,643,997	981,837
FHLB stock	32,529	21,819
Loans held for sale	735	2,563
Loans	0	0
FDIC loss-sharing asset	0	0
Interest rate contracts	9,044	14,921
Liabilities
Deposits	509,201	493,400
FHLB Advances	35,080	5,894
Repurchase agreements	26,361	26,464
Interest rate contracts	9,044	14,921
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Securities available for sale	0	0
FHLB stock	0	0
Loans held for sale	0	0
Loans	4,605,038	2,944,317
FDIC loss-sharing asset	11,248	26,543
Interest rate contracts	0	0
Liabilities
Deposits	0	0
FHLB Advances	0	0
Repurchase agreements	0	0
Interest rate contracts	0	0
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	165,030	124,573
Interest-earning deposits with banks	14,531	389,353
Securities available for sale	20,114	19,828
FHLB stock	0	0
Loans held for sale	0	0
Loans	0	0
FDIC loss-sharing asset	0	0
Interest rate contracts	0	0
Liabilities
Deposits	5,449,546	3,549,821
FHLB Advances	0	0
Repurchase agreements	0	0
Interest rate contracts	$ 0	$ 0