Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest income:
Loans, including fees	$ 205,847	$ 172,781
Loans held for sale	221	217
Securities-taxable	29,301	23,367
Securities-tax exempt	5,537	5,407
Short-term investments	489	743
Total interest income	241,395	202,515
Interest expense:
Deposits	26,959	12,819
Short-term borrowings	5,351	2,941
Long-term debt	3,421	5,064
Total interest expense	35,731	20,824
Net interest income	205,664	181,691
Provision for loan losses	12,253	15,991
Net interest income after provision for loan losses	193,411	165,700
Noninterest income:
Service charges on deposit accounts	21,448	19,206
Trust fees	11,335	11,211
Bank card and ATM fees	14,458	12,468
Investment and annuity fees and insurance commissions	6,125	5,264
Secondary mortgage market operations	3,401	3,567
Other income	9,485	11,775
Total noninterest income	66,252	63,491
Noninterest expense:
Compensation expense	80,100	73,099
Employee benefits	19,874	19,080
Personnel expense	99,974	92,179
Net occupancy expense	11,010	10,757
Equipment expense	3,546	3,714
Data processing expense	16,449	15,397
Professional services expense	9,255	11,276
Amortization of intangibles	5,618	4,705
Telecommunications and postage	3,850	3,467
Deposit insurance and regulatory fees	7,948	6,490
Other real estate (income) expense, net	210	(13)
Other expense	12,931	15,570
Total noninterest expense	170,791	163,542
Income before income taxes	88,872	65,649
Income taxes	16,397	16,635
Net income	$ 72,475	$ 49,014
Earnings per common share-basic	$ 0.83	$ 0.57
Earnings per common share-diluted	0.83	0.57
Dividends paid per share	$ 0.24	$ 0.24
Weighted average shares outstanding-basic	85,241	84,365
Weighted average shares outstanding-diluted	85,423	84,624