Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Interest and fees on loans	$ 217,212	$ 185,452	$ 137,738
Interest on debt securities:
Taxable	17,469	14,551	9,590
Nontaxable	1,074	1,283	1,300
Interest on interest-bearing deposits	1,141	804	370
Dividends on equity securities	906	449	226
Total interest income	237,802	202,539	149,224
Interest expense:
Interest-bearing transaction accounts	3,643	2,195	1,370
Money market accounts	19,361	8,708	4,439
Savings accounts	597	459	262
Certificates of Deposit	10,168	5,838	4,770
Subordinated debentures and notes	5,798	5,095	1,894
Federal Home Loan Bank advances	5,556	2,356	555
Notes payable and other borrowings	774	584	439
Total interest expense	45,897	25,235	13,729
Net interest income	191,905	177,304	135,495
Provision for loan losses, net	6,644	10,130	3,605
Net interest income after provision for loan losses	185,261	167,174	131,890
Noninterest income:
Service charges on deposit accounts	11,749	11,043	8,615
Wealth management revenue	8,241	8,102	6,729
Card services revenue	6,686	5,433	3,130
Gain on state tax credits, net	2,820	2,581	2,647
Gain on sale of other real estate	13	93	1,837
Gain on sale of investment securities	9	22	86
Miscellaneous income	8,829	7,120	6,015
Total noninterest income	38,347	34,394	29,059
Noninterest expense:
Employee compensation and benefits	66,039	61,388	49,846
Occupancy	9,550	9,057	6,889
Data processing	6,321	6,272	4,723
Professional fees	3,134	3,813	3,825
FDIC and other insurance	3,272	3,194	3,018
Loan legal and other real estate expense	1,088	2,220	1,635
Merger Related Expenses	1,271	6,462	1,386
Other	28,356	22,645	14,788
Total noninterest expense	119,031	115,051	86,110
Income before income tax expense	104,577	86,517	74,839
Income tax expense	15,360	38,327	26,002
Net income	$ 89,217	$ 48,190	$ 48,837
Earnings per common share
Basic (usd per share)	$ 3.86	$ 2.10	$ 2.44
Diluted (usd per share)	$ 3.83	$ 2.07	$ 2.41