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Loans and Allowance for Loan and Lease Losses - Loan Balances and Related ALLL (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	$ 185		$ 561
Allowance for loans collectively evaluated for impairment	17,300		13,050
Total allowance	17,485	$ 18,166	13,611	$ 12,086	$ 11,474	$ 13,506
Loans individually evaluated for impairment	16,135		15,563
Loans collectively evaluated for impairment	1,262,846		1,110,776
Total	1,278,981		1,126,339
Commercial
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	185		561
Allowance for loans collectively evaluated for impairment	10,747		8,322
Total allowance	10,932	11,487	8,883	7,520	6,809	8,071
Loans individually evaluated for impairment	10,166		9,056
Loans collectively evaluated for impairment	604,571		400,364
Total	614,737		409,420
Real Estate
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	0		0
Allowance for loans collectively evaluated for impairment	4,418		2,897
Total allowance	4,418	4,733	2,897	2,745	2,790	3,643
Loans individually evaluated for impairment	5,969		6,507
Loans collectively evaluated for impairment	551,474		597,782
Total	557,443		604,289
Construction and land development loans
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	0		0
Allowance for loans collectively evaluated for impairment	114		34
Total allowance	114	77	34	83	119	426
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	9,300		2,981
Total	9,300		2,981
Consumer and Single Family Mortgages
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	0		0
Allowance for loans collectively evaluated for impairment	2,021		1,797
Total allowance	2,021	1,869	1,797	1,738	1,756	1,290
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	97,501		109,649
Total	97,501		109,649
Unallocated
Financing Receivable, Allowance for Credit Loss
Allowance for loans individually evaluated for impairment	0		0
Allowance for loans collectively evaluated for impairment	0		0
Total allowance	0	$ 0	0	$ 0	$ 0	$ 76
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	0		0
Total	$ 0		$ 0