Fair Value Measurement (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Financial assets:
Cash and Cash Equivalents, at Carrying Value	$ 377,319	$ 523,113	$ 161,033	$ 178,406
Cash and due from banks, Fair Value	377,319	523,113
Investment securities, Carrying Amount	3,494,389	3,154,333
Investment securities, Fair Value	3,579,390	3,207,754
Loans Receivable Held-for-sale, Net	30,077	41,340
Loans Held-for-sale, Fair Value Disclosure	30,077	41,340
Noncovered Loans and Leases Receivable Net	7,641,245	7,087,398
Net noncovered loans, Fair Value	7,373,801	6,716,214
Net covered loans and loss share receivable, Carrying Amount	1,460,723	1,963,021
Net covered loans and loss share receivable, Fair Value	1,460,723	1,963,021
Accrued interest receivable, Carrying Amount	42,274	41,830
Accrued interest receivable, Fair Value	42,274	41,830
Mortgage servicing rights, Carrying Amount	17,640	21,317
Mortgage servicing rights, Fair Value	17,749	21,579
Derivative Assets	62,056	47,764
Derivative Asset, Fair Value, Gross Asset	62,056	47,764
Financial liabilities:
Deposits, Carrying Amount	11,431,609	11,268,006
Deposits, Fair Value	11,445,777	11,275,440
Total Federal funds purchased and securities sold under agreements to repurchase	866,265	777,585
Federal funds purchased and securities sold under agreements to repurchase, Fair Value	866,265	782,668
Wholesale borrowings, Carrying Amount	203,462	326,007
Wholesale borrowings, Fair Value	211,623	329,465
Accrued interest payable, Carrying Amount	3,915	6,560
Accrued interest payable, Fair Value	3,915	6,560
Derivative liabilities, Carrying Amount	86,106	72,824
Derivative liabilities, Fair Value	86,106	72,824
True up liability, Carrying Amount	11,551	12,061
True-up liability, Fair Value	$ 11,551	$ 12,061