Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Loans	$ 349,221	$ 279,931	$ 249,549
Mortgage-backed securities	14,037	15,300	16,034
Debt securities, equity investments and other	16,350	13,563	11,071
Total interest income	379,608	308,794	276,654
Interest expense:
Deposits	48,290	38,432	22,578
Borrowed funds	18,367	14,391	13,574
Total interest expense	66,657	52,823	36,152
Net interest income	312,951	255,971	240,502
Credit loss expense	59,404	1,636	3,490
Net interest income after credit loss expense	253,547	254,335	237,012
Other income:
Bankcard services revenue	11,417	10,263	9,228
Net gain on sales of loans	8,278	16	668
Net gain (loss) on equity investments	21,214	267	(199)
Net gain (loss) from other real estate operations	35	(330)	(3,812)
Income from bank owned life insurance	6,424	5,420	5,105
Commercial loan swap income	8,080	5,285	669
Other	618	642	1,462
Total other income	73,926	42,165	34,827
Operating expenses:
Compensation and employee benefits	114,155	89,912	83,135
Occupancy	20,782	17,159	17,915
Equipment	7,769	7,719	8,319
Marketing	3,117	3,469	3,415
Federal deposit insurance and regulatory assessments	4,871	2,227	3,713
Data processing	17,467	14,814	13,286
Check card processing	5,458	5,956	4,209
Professional fees	12,247	9,338	4,963
Other operating expense	16,552	14,968	13,509
Amortization of core deposit intangible	6,186	4,027	3,811
FHLB advance prepayment fees	14,257		0
Branch consolidation expenses	7,623	9,050	3,151
Merger related expenses	15,947	10,503	26,911
Total operating expenses	246,431	189,142	186,337
Income before provision for income taxes	81,042	107,358	85,502
Provision for income taxes	17,733	18,784	13,570
Net income	63,309	88,574	71,932
Dividends on preferred shares	(2,097)	0	0
Net income available to common stockholders	$ (61,212)	$ (88,574)	$ (71,932)
Basic earnings per share (in dollars per share)	$ 1.02	$ 1.77	$ 1.54
Diluted earnings per share (in dollars per share)	$ 1.02	$ 1.75	$ 1.51
Average basic shares outstanding (in shares)	59,919	50,166	46,773
Average diluted shares outstanding (in shares)	60,072	50,746	47,657
Trust and asset management revenue
Other income:
Trust and asset management revenue and fees and service charges	$ 2,052	$ 2,102	$ 2,245
Fees and service charges
Other income:
Trust and asset management revenue and fees and service charges	$ 15,808	$ 18,500	$ 19,461