Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INTEREST INCOME
Interest and fees on loans	$ 659,538	$ 615,627	$ 598,582
Interest and dividends on investment securities:
Taxable	95,152	100,292	102,464
Tax-exempt	32,049	31,152	29,064
Other interest	4,829	6,591	6,635
Total interest income	791,568	753,662	736,745
INTEREST EXPENSE
Interest on deposits	50,335	33,125	26,294
Interest on Federal funds purchased and securities sold under agreements to repurchase	1,314	943	1,219
Interest on other short-term funding	2,114	465	785
Interest on long-term funding	30,532	42,851	27,480
Total interest expense	84,295	77,384	55,778
NET INTEREST INCOME	707,273	676,278	680,967
Provision for credit losses	70,000	37,500	16,000
Net interest income after provision for credit losses	637,273	638,778	664,967
NONINTEREST INCOME
Trust service fees	46,867	48,840	48,403
Service charges on deposit accounts	66,609	65,471	68,779
Card-based and other nondeposit fees	50,077	47,912	47,114
Insurance commissions	80,795	75,363	44,421
Brokerage and annuity commissions	16,235	15,378	16,089
Mortgage banking, net	38,121	32,263	21,320
Capital market fees, net	22,059	14,558	12,862
Bank owned life insurance income	14,371	9,796	13,576
Asset gains (losses), net	(86)	2,540	10,830
Investment securities gains, net	9,316	8,133	494
Other	8,519	9,103	6,973
Total noninterest income	352,883	329,357	290,861
NONINTEREST EXPENSE
Personnel expense	414,837	404,741	390,399
Occupancy	56,069	60,896	57,677
Equipment	21,489	23,209	24,784
Technology	57,300	60,613	55,472
Business development and advertising	26,351	25,772	26,144
Other intangible amortization	2,093	3,094	3,747
Loan expense	13,641	14,102	13,866
Legal and professional fees	19,869	17,052	17,485
Foreclosure / OREO expense, net	4,844	5,442	7,264
FDIC expense	34,750	26,000	23,761
Other	51,317	57,426	59,184
Total noninterest expense	702,560	698,347	679,783
Income before income taxes	287,596	269,788	276,045
Income tax expense	87,322	81,487	85,536
Net income	200,274	188,301	190,509
Preferred stock dividends	8,903	7,155	5,002
Net income available to common equity	$ 191,371	$ 181,146	$ 185,507
Earnings per common share:
Basic (in usd per share)	$ 1.27	$ 1.20	$ 1.17
Diluted (in usd per share)	$ 1.26	$ 1.19	$ 1.16
Average common shares outstanding:
Basic (in shares)	148,769	149,350	157,286
Diluted (in shares)	149,961	150,603	158,254