Loans (Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	$ 9,527,797	$ 9,009,140
Covered loans	271,844	356,655
Total loans	9,799,641	9,365,795
FDIC loss-share receivable related to covered loans and foreclosed assets	74,390	89,359
Total Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	3,985,092	3,806,484
Total loans	4,152,717	4,018,283
Total Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	1,378,728	1,452,160
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	1,878,387	1,825,066
Covered loans	83,742	121,151
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	3,574,089	3,378,252
Covered loans	160,651	195,646
Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	411,003	428,232
Covered loans	6,974	16,153
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	2,285,590	1,925,430
Covered loans	15,546	17,026
Home Equity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	469,604	512,745
Automobile Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	772,490	850,801
Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-covered loans	136,634	88,614
Covered loans	$ 4,931	$ 6,679