CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest income:
Loans, including fees	$ 955,388	$ 850,472	$ 578,286
Securities:
Taxable	46,649	48,192	39,060
Tax-exempt	51,138	35,995	13,712
Federal funds sold and other	14,761	12,058	5,080
Total interest income	1,067,936	946,717	636,138
Interest expense:
Deposits	231,641	151,043	59,584
Securities sold under agreements to repurchase	570	588	406
Federal Home Loan Bank advances and other borrowings	69,583	58,744	32,842
Total interest expense	301,794	210,375	92,832
Net interest income	766,142	736,342	543,306
Provision for loan losses	27,283	34,377	23,664
Net interest income after provision for loan losses	738,859	701,965	519,642
Noninterest income:
Total noninterest income	263,826	200,870	144,904
Noninterest expense:
Salaries and employee benefits	313,359	271,673	209,662
Equipment and occupancy	84,582	74,276	54,092
Other real estate expense, net	4,228	723	1,079
Marketing and other business development	13,251	11,712	8,321
Postage and supplies	8,144	7,815	5,736
Amortization of intangibles	9,908	10,549	8,816
Merger related expenses	0	8,259	31,843
Other noninterest expense	71,676	67,880	47,011
Total noninterest expense	505,148	452,887	366,560
Income before income taxes	497,537	449,948	297,986
Income tax expense	96,656	90,508	124,007
Net income	$ 400,881	$ 359,440	$ 173,979
Per share information:
Basic net income per common share	$ 5.25	$ 4.66	$ 2.73
Diluted net income per common share	$ 5.22	$ 4.64	$ 2.70
Weighted average common shares outstanding:
Basic	76,364,303	77,111,372	63,760,578
Diluted	76,763,903	77,449,917	64,328,189
Service charges on deposit accounts
Noninterest income:
Total noninterest income	$ 36,769	$ 24,906	$ 20,034
Investment services
Noninterest income:
Total noninterest income	24,187	21,175	14,315
Insurance sales commissions
Noninterest income:
Total noninterest income	9,344	9,331	7,405
Gain on mortgage loans sold, net
Noninterest income:
Total noninterest income	24,335	14,564	18,625
Investment gains (losses) on sales, net
Noninterest income:
Total noninterest income	(5,941)	(2,254)	(8,265)
Trust fees
Noninterest income:
Total noninterest income	14,184	13,143	8,664
Income from equity method investment
Noninterest income:
Total noninterest income	90,111	51,222	37,958
Other noninterest income
Noninterest income:
Total noninterest income	$ 70,837	$ 68,783	$ 46,168