Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Interest income:
Loans, including fees	$ 122,600	$ 112,586
Securities:
Taxable	25,302	25,974
Tax-exempt	56,947	50,333
Interest-bearing deposits	6,836	3,653
Federal funds sold and resell agreements	107	58
Total interest income	211,792	192,604
Interest expense:
Deposits	1,868	1,787
Federal funds purchased and repurchase agreements	139	56
Junior subordinated deferrable interest debentures	908	750
Other long-term borrowings	368	287
Total interest expense	3,283	2,880
Net interest income	208,509	189,724
Provision for loan losses	7,952	28,500
Net interest income after provision for loan losses	200,557	161,224
Non-interest income:
Trust and investment management fees	26,470	25,334
Service charges on deposit accounts	20,769	20,364
Insurance commissions and fees	13,821	15,423
Interchange and debit card transaction fees	5,574	5,022
Other charges, commissions and fees	9,592	9,053
Net gain (loss) on securities transactions	0	14,903
Other	7,474	6,044
Total non-interest income	83,700	96,143
Non-interest expense:
Salaries and wages	82,512	79,297
Employee benefits	21,625	20,305
Net occupancy	19,237	17,187
Furniture and equipment	17,990	17,517
Deposit insurance	4,915	3,657
Intangible amortization	458	664
Other	41,178	40,532
Total non-interest expense	187,915	179,159
Income before income taxes	96,342	78,208
Income taxes	11,401	9,392
Net income	84,941	68,816
Preferred stock dividends	2,016	2,016
Net income available to common shareholders	$ 82,925	$ 66,800
Earnings per common share:
Basic	$ 1.29	$ 1.07
Diluted	$ 1.28	$ 1.07