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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Loans - Allowance for loan losses by segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Allowance for Loan Losses:
Beginning Balance				$ 20,031				$ 16,502	$ 20,031	$ 16,502	$ 12,333
Provision for Loan Losses	$ 600	$ 900	$ 600	600	$ 800	$ 1,275	$ 900	600	2,700	3,575	4,175
Loans Charged-off									(388)	(421)	(177)
Recoveries of Loans									183	375	171
Total Ending Allowance Balance	22,526				20,031				22,526	20,031	16,502
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Individually Evaluated for Impairment												$ 45	$ 47
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												22,481	19,984
Loans and Leases Receivable, Allowance, Total	22,526			20,031	20,031			16,502	22,526	20,031	16,502	22,526	20,031
Loans, Individually Evaluated for Impairment												1,758	2,305
Loans, Collectively Evaluated for Impairment												1,910,280	1,662,626
Totals												1,912,038	1,664,931
Commercial
Allowance for Loan Losses:
Beginning Balance				2,898				2,435	2,898	2,435	1,315
Provision for Loan Losses									312	448	1,116
Loans Charged-off									(160)	(10)	(1)
Recoveries of Loans									8	25	5
Total Ending Allowance Balance	3,058				2,898				3,058	2,898	2,435
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Individually Evaluated for Impairment												31	8
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												3,027	2,890
Loans and Leases Receivable, Allowance, Total	3,058			2,898	2,898			2,435	3,058	2,898	2,435	3,058	2,898
Loans, Individually Evaluated for Impairment												273	8
Loans, Collectively Evaluated for Impairment												275,762	260,825
Totals												276,035	260,833
Construction and Land Development
Allowance for Loan Losses:
Beginning Balance				2,451				1,892	2,451	1,892	1,379
Provision for Loan Losses									(250)	632	488
Loans Charged-off										(358)
Recoveries of Loans									1	285	25
Total Ending Allowance Balance	2,202				2,451				2,202	2,451	1,892
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												2,202	2,451
Loans and Leases Receivable, Allowance, Total	2,202			2,451	2,451			1,892	2,202	2,451	1,892	2,202	2,451
Loans, Individually Evaluated for Impairment												176	198
Loans, Collectively Evaluated for Impairment												196,600	209,843
Totals												196,776	210,041
1-4 Family Mortgage
Allowance for Loan Losses:
Beginning Balance				2,597				2,317	2,597	2,317	2,410
Provision for Loan Losses									269	242	(230)
Loans Charged-off									(195)	(21)
Recoveries of Loans									168	59	137
Total Ending Allowance Balance	2,839				2,597				2,839	2,597	2,317
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Individually Evaluated for Impairment													17
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												2,839	2,580
Loans and Leases Receivable, Allowance, Total	2,839			2,597	2,597			2,317	2,839	2,597	2,317	2,839	2,597
Loans, Individually Evaluated for Impairment												1,059	1,676
Loans, Collectively Evaluated for Impairment												259,552	225,097
Totals												260,611	226,773
Multifamily
Allowance for Loan Losses:
Beginning Balance				4,644				3,170	4,644	3,170	1,568
Provision for Loan Losses									1,180	1,474	1,602
Total Ending Allowance Balance	5,824				4,644				5,824	4,644	3,170
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												5,824	4,644
Loans and Leases Receivable, Allowance, Total	5,824			4,644	4,644			3,170	5,824	4,644	3,170	5,824	4,644
Loans, Collectively Evaluated for Impairment												515,014	407,934
Totals												515,014	407,934
CRE Owner Occupied
Allowance for Loan Losses:
Beginning Balance				808				956	808	956	1,160
Provision for Loan Losses									(16)	(148)	(204)
Total Ending Allowance Balance	792				808				792	808	956
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Individually Evaluated for Impairment													22
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												792	786
Loans and Leases Receivable, Allowance, Total	792			808	808			956	792	808	956	792	808
Loans, Individually Evaluated for Impairment												236	365
Loans, Collectively Evaluated for Impairment												66,348	64,093
Totals												66,584	64,458
CRE Non-owner Occupied
Allowance for Loan Losses:
Beginning Balance				5,872				5,087	5,872	5,087	3,323
Provision for Loan Losses									1,100	785	1,875
Loans Charged-off											(111)
Total Ending Allowance Balance	6,972				5,872				6,972	5,872	5,087
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												6,972	5,872
Loans and Leases Receivable, Allowance, Total	6,972			5,872	5,872			5,087	6,972	5,872	5,087	6,972	5,872
Loans, Collectively Evaluated for Impairment												592,545	490,632
Totals												592,545	490,632
Consumer and other
Allowance for Loan Losses:
Beginning Balance				65				60	65	60	78
Provision for Loan Losses									47	31	43
Loans Charged-off									(33)	(32)	(65)
Recoveries of Loans									6	6	4
Total Ending Allowance Balance	85				65				85	65	60
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Individually Evaluated for Impairment												14
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												71	65
Loans and Leases Receivable, Allowance, Total	85			65	65			60	85	65	60	85	65
Loans, Individually Evaluated for Impairment												14	58
Loans, Collectively Evaluated for Impairment												4,459	4,202
Totals												4,473	4,260
Unallocated
Allowance for Loan Losses:
Beginning Balance				696				585	696	585	1,100
Provision for Loan Losses									58	111	(515)
Total Ending Allowance Balance	754				696				754	696	585
Allowance for loan losses and the recorded investment
Allowance for Loan Losses and Loans, Collectively Evaluated for Impairment												754	696
Loans and Leases Receivable, Allowance, Total	$ 754			$ 696	$ 696			$ 585	$ 754	$ 696	$ 585	$ 754	$ 696