CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income:
Interest and fees on loans	$ 393,477	$ 316,550	$ 293,131
Interest on loans held for sale	1,686	1,607	1,245
Interest on deposits with banks	446	2,129	1,304
Interest and dividends on investment securities:
Taxable for federal income taxes	22,136	21,739	20,516
Exempt from federal income taxes	5,814	5,834	7,855
Interest on federal funds sold	1	10	31
Total interest income	423,560	347,869	324,082
Interest expense:
Interest on deposits	41,651	61,681	39,139
Interest on retail repurchase agreements and federal funds purchased	1,965	1,161	1,169
Interest on advances from FHLB	6,593	16,578	21,408
Interest on subordinated debt	10,192	3,141	1,921
Total interest expense	60,401	82,561	63,637
Net interest income	363,159	265,308	260,445
Provision for credit losses	85,669	4,684	9,023
Net interest income after provision for credit losses	277,490	260,624	251,422
Non-interest income:
Investment securities gains	467	77	190
Insurance agency commissions	6,795	6,612	6,158
Income from bank owned life insurance	2,867	3,165	4,327
Other income	9,221	8,780	7,126
Total non-interest income	102,716	71,322	61,049
Non-interest expense:
Salaries and employee benefits	134,471	103,950	96,998
Occupancy expense of premises	21,383	19,470	18,352
Equipment expenses	12,224	10,720	9,335
Marketing	4,281	4,456	3,924
Outside data services	8,759	7,567	6,603
FDIC insurance	4,727	2,260	5,095
Amortization of intangible assets	6,221	1,946	2,162
Merger and acquisition expense	25,174	1,312	11,766
Professional fees and services	7,939	6,978	6,056
Other expenses	30,603	20,426	19,492
Total non-interest expense	255,782	179,085	179,783
Income before income tax expense	124,424	152,861	132,688
Income tax expense	27,471	36,428	31,824
Net income	$ 96,953	$ 116,433	$ 100,864
Net income per common share amounts:
Basic net income per common share (in dollars per share)	$ 2.19	$ 3.25	$ 2.82
Diluted net income per common share (in dollars per share)	2.18	3.25	2.82
Dividends declared per share (in dollars per share)	$ 1.20	$ 1.18	$ 1.10
Service charges on deposit accounts
Non-interest income:
Fees and commissions, mortgage banking and servicing	$ 7,066	$ 9,692	$ 9,324
Mortgage banking activities
Non-interest income:
Fees and commissions, mortgage banking and servicing	40,058	14,711	7,073
Wealth management income
Non-interest income:
Fees and commissions, mortgage banking and servicing	30,570	22,669	21,284
Bank card fees
Non-interest income:
Fees and commissions, mortgage banking and servicing	$ 5,672	$ 5,616	$ 5,567