Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Assets:
Cash and due from banks	$ 542,447	$ 790,106	$ 623,204
Interest-bearing deposits	2,659,691	2,650,425	1,497,478
Federal funds sold and resell agreements	16,322	84,448	8,052
Total cash and cash equivalents	3,218,460	3,524,979	2,128,734
Securities held to maturity, at amortized cost	3,068,008	2,956,381	365,603
Securities available for sale, at estimated fair value	5,857,525	6,203,299	8,568,215
Trading account securities	22,664	30,074	16,846
Loans, net of unearned discounts	9,162,351	9,223,848	8,126,713
Less: Allowance for loan losses	(93,589)	(104,453)	(107,181)
Net loans	9,068,762	9,119,395	8,019,532
Premises and equipment, net	303,321	315,934	321,681
Goodwill	535,509	535,509	535,560
Other intangible assets, net	7,327	8,147	11,033
Cash surrender value of life insurance policies	138,898	138,005	135,035
Accrued interest receivable and other assets	277,247	292,346	314,942
Total assets	22,497,721	23,124,069	20,417,181
Liabilities:
Non-interest-bearing demand deposits	7,675,466	8,096,937	6,784,112
Interest-bearing deposits	11,368,438	11,400,429	10,124,909
Total deposits	19,043,904	19,497,366	16,909,021
Federal funds purchased and repurchase agreements	510,102	561,061	637,098
Junior subordinated deferrable interest debentures	123,712	123,712	123,712
Other long-term borrowings	100,002	100,007	100,022
Accrued interest payable and other liabilities	276,670	424,441	326,615
Total liabilities	20,054,390	20,706,587	18,096,468
Shareholders' Equity:
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized; 6,000,000 Series A shares ($25 liquidation preference) issued at March 31, 2013, none issued at December 31, 2012 or March 31, 2012	144,676
Common stock, par value $0.01 per share; 210,000,000 shares authorized; 61,632,464 shares issued at March 31, 2013, 61,479,189 shares issued at December 31, 2012 and 61,372,763 shares issued at March 31, 2012	616	615	614
Additional paid-in capital	684,141	702,968	688,150
Retained earnings	1,500,085	1,475,851	1,387,553
Accumulated other comprehensive income, net of tax	214,370	238,048	244,396
Treasury stock, 1,662,927 shares at March 31, 2013, at cost	(100,557)
Total shareholders' equity	2,443,331	2,417,482	2,320,713
Total liabilities and shareholders' equity	$ 22,497,721	$ 23,124,069	$ 20,417,181