Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
INTEREST INCOME
Loans	$ 157,261	$ 126,134
Securities:
Taxable interest	25,391	19,780
Tax-exempt interest	20,697	18,703
Total securities income	46,088	38,483
Federal funds and resell agreements	3,625	1,038
Interest-bearing due from banks	3,899	1,580
Trading securities	434	430
Total interest income	211,307	167,665
INTEREST EXPENSE
Deposits	37,834	13,835
Federal funds and repurchase agreements	8,264	4,732
Other	1,341	1,176
Total interest expense	47,439	19,743
Net interest income	163,868	147,922
Provision for loan losses	12,350	10,000
Net interest income after provision for loan losses	151,518	137,922
NONINTEREST INCOME
Trading and investment banking	5,581	4,101
Gain on sales of securities available for sale, net	809	139
Other	13,106	10,601
Total noninterest income	107,382	105,525
NONINTEREST EXPENSE
Salaries and employee benefits	116,032	107,968
Occupancy, net	11,743	10,953
Equipment	19,684	18,826
Supplies and services	3,873	3,760
Marketing and business development	4,913	5,034
Processing fees	12,132	11,161
Legal and consulting	5,633	3,844
Bankcard	4,345	4,626
Amortization of other intangible assets	1,327	1,562
Regulatory fees	2,890	2,905
Other	8,054	5,237
Total noninterest expense	190,626	175,876
Income before income taxes	68,274	67,571
Income tax expense	10,530	10,038
Income from continuing operations	57,744	57,533
Discontinued Operations
Loss from discontinued operations before income taxes		(917)
Income tax benefit		(170)
Loss from discontinued operations		(747)
NET INCOME	$ 57,744	$ 56,786
Basic:
Income from continuing operations	$ 1.19	$ 1.16
Loss from discontinued operations		(0.01)
Net income – basic	1.19	1.15
Diluted:
Income from continuing operations	1.18	1.15
Loss from discontinued operations		(0.01)
Net income – diluted	1.18	1.14
Dividends	$ 0.300	$ 0.290
Weighted average shares outstanding – basic	48,712,153	49,420,606
Weighted average shares outstanding – diluted	48,998,571	49,917,454
Trust and Securities Processing [Member]
NONINTEREST INCOME
Noninterest income	$ 41,957	$ 44,002
Service Charges On Deposit Accounts [Member]
NONINTEREST INCOME
Noninterest income	21,281	21,905
Insurance Fees and Commissions [Member]
NONINTEREST INCOME
Noninterest income	338	301
Brokerage Fees [Member]
NONINTEREST INCOME
Noninterest income	7,243	6,353
Bankcard Fees [Member]
NONINTEREST INCOME
Noninterest income	$ 17,067	$ 18,123