Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest income:
Loans, including fees	$ 111,087	$ 116,078	$ 324,858	$ 330,998
Securities:
Taxable	27,518	22,855	85,607	66,372
Tax-exempt	49,518	39,635	144,117	113,168
Interest-bearing deposits	1,937	2,960	5,743	8,045
Federal funds sold and resell agreements	28	20	69	63
Total interest income	190,088	181,548	560,394	518,646
Interest expense:
Deposits	2,138	2,991	7,076	8,119
Federal funds purchased and repurchase agreements	39	35	113	96
Junior subordinated deferrable interest debentures	689	659	2,016	1,821
Other long-term borrowings	241	222	696	668
Total interest expense	3,107	3,907	9,901	10,704
Net interest income	186,981	177,641	550,493	507,942
Provision for loan losses	6,810	390	17,845	11,914
Net interest income after provision for loan losses	180,171	177,251	532,648	496,028
Non-interest income:
Trust and investment management fees	25,590	26,807	79,223	78,966
Service charges on deposit accounts	20,854	20,819	60,664	61,255
Insurance commissions and fees	11,763	11,348	36,528	34,297
Interchange and debit card transaction fees	5,031	4,719	14,591	13,589
Other charges, commissions and fees	10,016	9,804	28,570	26,561
Net gain (loss) on securities transactions	(52)	33	176	35
Other	10,176	7,332	25,823	22,799
Total non-interest income	83,378	80,862	245,575	237,502
Non-interest expense:
Salaries and wages	79,552	73,756	232,257	214,446
Employee benefits	16,210	14,639	53,776	46,833
Net occupancy	17,380	14,049	48,890	40,735
Furniture and equipment	16,286	16,078	47,469	46,238
Deposit insurance	3,676	3,421	10,852	9,683
Intangible amortization	816	1,052	2,559	2,524
Other	41,649	40,856	124,516	125,280
Total non-interest expense	175,569	163,851	520,319	485,739
Income before income taxes	87,980	94,262	257,904	247,791
Income taxes	12,130	16,881	36,814	42,518
Net income	75,850	77,381	221,090	205,273
Preferred stock dividends	2,016	2,016	6,047	6,047
Net income available to common shareholders	$ 73,834	$ 75,365	$ 215,043	$ 199,226
Earnings per common share:
Basic	$ 1.18	$ 1.19	$ 3.41	$ 3.20
Diluted	$ 1.17	$ 1.18	$ 3.39	$ 3.18