Loans and Allowance for Loan and Lease Losses - Summary of Activity in ALLL (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Allowance for Loan and Lease Losses
Balance at beginning of period	$ 18,166	$ 11,474	$ 13,611	$ 13,506
Charge offs	(840)	(1,551)	(5,401)	(7,376)
Recoveries	159	63	225	556
Provision	0	2,100	9,050	5,400
Balance at end of period	17,485	12,086	17,485	12,086
Commercial
Allowance for Loan and Lease Losses
Balance at beginning of period	11,487	6,809	8,883	8,071
Charge offs	(839)	(1,549)	(5,317)	(7,337)
Recoveries	128	58	187	541
Provision	156	2,202	7,179	6,245
Balance at end of period	10,932	7,520	10,932	7,520
Real  Estate
Allowance for Loan and Lease Losses
Balance at beginning of period	4,733	2,790	2,897	3,643
Charge offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(315)	(45)	1,521	(898)
Balance at end of period	4,418	2,745	4,418	2,745
Construction and land development loans
Allowance for Loan and Lease Losses
Balance at beginning of period	77	119	34	426
Charge offs	0	0	0	0
Recoveries	0	0	0	0
Provision	37	(36)	80	(343)
Balance at end of period	114	83	114	83
Consumer  and Single Family Mortgages
Allowance for Loan and Lease Losses
Balance at beginning of period	1,869	1,756	1,797	1,290
Charge offs	(1)	(2)	(84)	(39)
Recoveries	31	5	38	15
Provision	122	(21)	270	472
Balance at end of period	2,021	1,738	2,021	1,738
Unallocated
Allowance for Loan and Lease Losses
Balance at beginning of period	0	0	0	76
Charge offs	0	0	0	0
Recoveries	0	0	0	0
Provision	0	0	0	(76)
Balance at end of period	$ 0	$ 0	$ 0	$ 0