Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Interest income:
Loans, including fees	$ 113,349	$ 108,105	$ 225,935	$ 213,771
Securities:
Taxable	25,531	27,917	51,505	58,089
Tax-exempt	50,910	48,053	101,243	94,599
Interest-bearing deposits	3,602	1,836	7,255	3,806
Federal funds sold and resell agreements	59	21	117	41
Total interest income	193,451	185,932	386,055	370,306
Interest expense:
Deposits	1,773	2,182	3,560	4,938
Federal funds purchased and repurchase agreements	52	38	108	74
Junior subordinated deferrable interest debentures	803	672	1,553	1,327
Other long-term borrowings	321	231	608	455
Total interest expense	2,949	3,123	5,829	6,794
Net interest income	190,502	182,809	380,226	363,512
Provision for loan losses	9,189	2,873	37,689	11,035
Net interest income after provision for loan losses	181,313	179,936	342,537	352,477
Non-interest income:
Trust and investment management fees	26,021	26,472	51,355	53,633
Service charges on deposit accounts	19,865	20,033	40,229	39,810
Insurance commissions and fees	9,360	10,130	24,783	24,765
Interchange and debit card transaction fees	5,381	4,917	10,403	9,560
Other charges, commissions and fees	10,069	10,113	19,122	18,554
Net gain (loss) on securities transactions	0	0	14,903	228
Other	7,321	7,317	13,365	15,647
Total non-interest income	78,017	78,982	174,160	162,197
Non-interest expense:
Salaries and wages	78,106	76,633	157,403	152,705
Employee benefits	17,712	17,339	38,017	37,566
Net occupancy	18,242	16,429	35,429	31,510
Furniture and equipment	17,978	15,649	35,495	31,183
Deposit insurance	4,197	3,563	7,854	7,176
Intangible amortization	619	849	1,283	1,743
Other	42,591	42,777	83,123	82,867
Total non-interest expense	179,445	173,239	358,604	344,750
Income before income taxes	79,885	85,679	158,093	169,924
Income taxes	8,406	12,602	17,835	24,684
Net income	71,479	73,077	140,258	145,240
Preferred stock dividends	2,015	2,015	4,031	4,031
Net income available to common shareholders	$ 69,464	$ 71,062	$ 136,227	$ 141,209
Earnings per common share:
Basic	$ 1.12	$ 1.12	$ 2.19	$ 2.23
Diluted	$ 1.11	$ 1.11	$ 2.18	$ 2.22