Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
INTEREST INCOME
Loans	$ 461,301	$ 386,274	$ 308,325
Securities:
Taxable interest	73,125	73,560	75,327
Tax-exempt interest	73,419	57,516	43,598
Total securities income	146,544	131,076	118,925
Federal funds and resell agreements	3,700	2,708	697
Interest-bearing due from banks	3,871	2,341	2,356
Trading securities	1,496	632	378
Total interest income	616,912	523,031	430,681
INTEREST EXPENSE
Deposits	36,354	17,936	14,269
Federal funds and repurchase agreements	17,906	6,524	1,785
Other	3,739	3,248	2,560
Total interest expense	57,999	27,708	18,614
Net interest income	558,913	495,323	412,067
Provision for loan losses	41,000	32,500	15,500
Net interest income after provision for loan losses	517,913	462,823	396,567
NONINTEREST INCOME
Trust and securities processing	176,646	166,315	166,261
Trading and investment banking	23,183	21,422	20,218
Service charges on deposit accounts	87,680	86,662	86,460
Insurance fees and commissions	1,972	4,188	2,530
Brokerage fees	23,208	17,833	11,753
Bankcard fees	73,030	68,749	69,211
Gains on sales of securities available for sale, net	4,192	8,509	10,402
Equity (losses) earnings on alternative investments	(1,108)	2,695	(12,188)
Other	34,759	26,138	16,012
Total noninterest income	423,562	402,511	370,659
NONINTEREST EXPENSE
Salaries and employee benefits	413,830	390,059	367,606
Occupancy, net	44,462	44,255	43,274
Equipment	72,008	66,337	62,571
Supplies and services	17,173	18,535	17,988
Marketing and business development	21,469	21,208	21,996
Processing fees	42,331	36,005	36,149
Legal and consulting	23,406	20,801	26,186
Bankcard	19,471	20,757	20,288
Amortization of other intangible assets	7,326	8,695	8,171
Regulatory fees	15,527	14,178	12,125
Other	28,126	25,915	22,584
Total noninterest expense	705,129	666,745	638,938
Income before income taxes	236,346	198,589	128,288
Income tax expense	53,370	44,955	31,730
Income from continuing operations	182,976	153,634	96,558
Discontinued Operations
Income from discontinued operations before taxes	101,226	8,415	30,997
Income tax expense	37,097	3,248	11,482
Income from discontinued operations	64,129	5,167	19,515
NET INCOME	$ 247,105	$ 158,801	$ 116,073
Basic:
Income from continuing operations	$ 3.72	$ 3.15	$ 2.05
Income from discontinued operations	1.30	0.10	0.41
Net income – basic	5.02	3.25	2.46
Diluted:
Income from continuing operations	3.67	3.12	2.03
Income from discontinued operations	1.29	0.10	0.41
Net income - diluted	$ 4.96	$ 3.22	$ 2.44
Weighted average shares outstanding – basic	49,223,661	48,828,313	47,126,252
Weighted average shares outstanding – diluted	49,839,290	49,277,055	47,579,334