Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest income:
Loans, including fees	$ 108,105	$ 110,605	$ 213,771	$ 214,920
Securities:
Taxable	27,917	22,114	58,089	43,517
Tax-exempt	48,053	37,969	94,599	73,533
Interest-bearing deposits	1,836	2,681	3,806	5,085
Federal funds sold and resell agreements	21	23	41	43
Total interest income	185,932	173,392	370,306	337,098
Interest expense:
Deposits	2,182	2,567	4,938	5,128
Federal funds purchased and repurchase agreements	38	34	74	61
Junior subordinated deferrable interest debentures	672	601	1,327	1,162
Other long-term borrowings	231	224	455	446
Total interest expense	3,123	3,426	6,794	6,797
Net interest income	182,809	169,966	363,512	330,301
Provision for loan losses	2,873	4,924	11,035	11,524
Net interest income after provision for loan losses	179,936	165,042	352,477	318,777
Non-interest income:
Trust and investment management fees	26,472	26,748	53,633	52,159
Service charges on deposit accounts	20,033	20,462	39,810	40,436
Insurance commissions and fees	10,130	9,823	24,765	22,949
Interchange and debit card transaction fees	4,917	4,627	9,560	8,870
Other charges, commissions and fees	10,113	8,550	18,554	16,757
Net gain (loss) on securities transactions	0	2	228	2
Other	7,317	8,938	15,647	15,467
Total non-interest income	78,982	79,150	162,197	156,640
Non-interest expense:
Salaries and wages	76,633	70,473	152,705	140,690
Employee benefits	17,339	14,806	37,566	32,194
Net occupancy	16,429	13,733	31,510	26,686
Furniture and equipment	15,649	15,207	31,183	30,160
Deposit insurance	3,563	3,145	7,176	6,262
Intangible amortization	849	783	1,743	1,472
Other	42,777	45,800	82,867	84,424
Total non-interest expense	173,239	163,947	344,750	321,888
Income before income taxes	85,679	80,245	169,924	153,529
Income taxes	12,602	13,541	24,684	25,637
Net income	73,077	66,704	145,240	127,892
Preferred stock dividends	2,015	2,015	4,031	4,031
Net income available to common shareholders	$ 71,062	$ 64,689	$ 141,209	$ 123,861
Earnings per common share:
Basic	$ 1.12	$ 1.04	$ 2.23	$ 2.01
Diluted	$ 1.11	$ 1.03	$ 2.22	$ 1.99