CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INTEREST INCOME:
Loans, including fees	$ 260,064	$ 237,621	$ 205,582
Taxable investment securities	13,546	11,830	9,404
Federal Home Loan Bank stock and other	7,273	6,730	3,792
Total interest income	280,883	256,181	218,778
INTEREST EXPENSE:
Deposits	29,135	17,017	9,802
Securities sold under agreements to repurchase and other short-term borrowings	1,211	1,125	502
Federal Home Loan Bank advances	12,791	10,473	8,860
Subordinated note	1,620	1,508	1,094
Total interest expense	44,757	30,123	20,258
NET INTEREST INCOME	236,126	226,058	198,520
Provision for loan and lease losses	25,758	31,368	27,704
NET INTEREST INCOME AFTER PROVISION FOR LOAN AND LEASE LOSSES	210,368	194,690	170,816
NONINTEREST INCOME:
Service charges on deposit accounts	14,197	14,273	13,357
Net refund transfer fees	21,158	20,029	18,500
Mortgage banking income	9,499	4,825	4,642
Interchange fee income	11,859	11,159	9,881
Program fees	4,712	6,225	5,824
Increase in cash surrender value of bank owned life insurance	1,550	1,527	1,562
Net losses on debt securities			(136)
Net gains on other real estate owned	540	729	676
Net gain on branch divestiture	7,829
Other	3,664	4,658	4,108
Total noninterest income	75,008	63,425	58,414
NONINTEREST EXPENSE:
Salaries and employee benefits	99,181	91,189	82,233
Occupancy and equipment, net	25,868	24,883	24,019
Communication and transportation	4,447	4,785	4,711
Marketing and development	5,023	4,432	5,188
FDIC insurance expense	743	1,494	1,378
Bank franchise tax expense	5,293	4,951	4,626
Data processing	9,189	9,613	7,748
Interchange related expense	4,870	4,480	3,988
Supplies	1,693	1,444	1,594
Other real estate owned and other repossession expense	326	94	388
Legal and professional fees	3,357	3,459	2,410
Impairment of premises held for sale	256	482	1,175
Other	11,937	12,546	11,386
Total noninterest expense	172,183	163,852	150,844
INCOME BEFORE INCOME TAX EXPENSE	113,193	94,263	78,386
INCOME TAX EXPENSE	21,494	16,411	32,754
NET INCOME	$ 91,699	$ 77,852	$ 45,632
Class A Common Stock
BASIC EARNINGS PER SHARE:
Basic earnings per share (in dollars per share)	$ 4.41	$ 3.76	$ 2.21
DILUTED EARNINGS PER SHARE:
Diluted earnings per share (in dollars per share)	4.39	3.74	2.20
Class B Common Stock
BASIC EARNINGS PER SHARE:
Basic earnings per share (in dollars per share)	4.01	3.41	2.01
DILUTED EARNINGS PER SHARE:
Diluted earnings per share (in dollars per share)	$ 3.99	$ 3.40	$ 2.00