Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income:
Interest and fees on loans	$ 69,628	$ 52,948	$ 130,653	$ 103,398
Interest on debt securities:
Taxable	7,757	4,228	13,232	8,215
Nontaxable	861	271	1,308	553
Interest on interest-bearing deposits	703	231	1,150	471
Dividends on equity securities	252	201	475	406
Total interest income	79,201	57,879	146,818	113,043
Interest expense:
Interest-bearing transaction accounts	2,134	817	3,924	1,623
Money market accounts	6,996	4,445	13,511	7,798
Savings accounts	231	147	414	272
Certificates of deposit	3,758	2,338	7,090	4,237
Subordinated debentures and notes	1,958	1,454	3,606	2,822
Federal Home Loan Bank advances	1,696	1,448	3,094	2,706
Notes payable and other borrowings	713	182	1,121	366
Total interest expense	17,486	10,831	32,760	19,824
Net interest income	61,715	47,048	114,058	93,219
Provision for loan losses	1,722	390	3,198	2,261
Net interest income after provision for loan losses	59,993	46,658	110,860	90,958
Noninterest income:
Total noninterest income	11,964	9,693	21,194	19,235
Noninterest expense:
Employee compensation and benefits	20,687	16,582	40,039	33,073
Occupancy	3,188	2,342	5,825	4,748
Data processing	2,458	1,533	4,364	3,000
Professional fees	1,037	747	1,783	1,596
FDIC and other insurance	815	920	1,663	1,837
Loan legal and other real estate expense	818	(23)	1,300	276
Merger related expenses	10,306	0	17,576	0
Other	9,745	7,118	16,342	13,832
Total noninterest expense	49,054	29,219	88,892	58,362
Income before income tax expense	22,903	27,132	43,162	51,831
Income tax expense	4,479	4,881	8,582	8,659
Net income	$ 18,424	$ 22,251	$ 34,580	$ 43,172
Earnings per common share
Basic (usd per share)	$ 0.69	$ 0.96	$ 1.36	$ 1.87
Diluted (usd per share)	$ 0.68	$ 0.95	$ 1.36	$ 1.85
Deposit Account [Member]
Noninterest income:
Total noninterest income	$ 3,366	$ 3,007	$ 6,301	$ 5,858
Fiduciary and Trust [Member]
Noninterest income:
Total noninterest income	2,661	2,141	4,653	4,255
Card Services Revenue [Member]
Noninterest income:
Total noninterest income	2,461	1,650	4,251	3,166
Other real estate
Noninterest income:
Total noninterest income	(18)	0	48	0
Tax credit activity, net [Member]
Noninterest income:
Total noninterest income	572	64	730	316
Financial Service, Other [Member]
Noninterest income:
Total noninterest income	$ 2,922	$ 2,831	$ 5,211	$ 5,640