Consolidated Balance Sheets (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and due from banks	$ 444,113	$ 455,482
Interest-bearing deposits in other financial institutions	571,924	126,018
Federal funds sold and securities purchased under agreements to resell	16,030	20,745
Investment securities held to maturity at amortized cost	404,455	175,210
Investment securities available for sale, at fair value	5,396,812	5,250,585
Federal Home Loan Bank and Federal Reserve Bank stocks, at cost	189,107	181,249
Loans held for sale	154,935	64,738
Loans	17,593,846	15,896,261
Allowance for loan losses	(266,302)	(268,315)
Loans, net	17,327,544	15,627,946
Premises and equipment, net	274,688	270,890
Goodwill	929,168	929,168
Other intangible assets, net	67,582	74,464
Trading assets	35,163	43,728
Other assets	1,010,253	1,006,697
Total assets	26,821,774	24,226,920
LIABILITIES AND STOCKHOLDERS' EQUITY
Noninterest-bearing demand deposits	4,505,272	4,626,312
Interest-bearing deposits	14,258,232	12,640,855
Total deposits	18,763,504	17,267,167
Federal funds purchased and securities sold under agreements to repurchase	493,991	475,442
Other short-term funding	574,297	265,484
Long-term funding	3,930,117	3,087,267
Trading liabilities	37,329	46,470
Accrued expenses and other liabilities	222,285	193,800
Total liabilities	24,021,523	21,335,630
Stockholders' equity
Preferred equity	59,727	61,862
Common stock	1,665	1,750
Surplus	1,484,933	1,617,990
Retained earnings	1,497,818	1,392,508
Accumulated other comprehensive income (loss)	(4,850)	(24,244)
Treasury stock, at cost	(239,042)	(158,576)
Total stockholders' equity	2,800,251	2,891,290
Total liabilities and stockholders' equity	$ 26,821,774	$ 24,226,920
Preferred shares issued	61,356	63,549
Preferred shares authorized (par value $1.00 per share)	750,000	750,000
Common shares issued	166,544,252	175,012,686
Common shares authorized (par value $0.01 per share)	250,000,000	250,000,000
Treasury shares of common stock	15,002,318	10,874,182