Loans and Allowance for Loan Losses Schedule of Allowance for Loan Loss Activity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		$ 17,235	$ 16,689
Allowance for loan losses, charge-offs		(1)	0
Allowance for loan losses, recoveries		98	48
Provision for loan losses	[1]	1,000	0
Allowance for loan losses, ending balance		18,332	16,737
Commercial [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		3,875	3,508
Allowance for loan losses, charge-offs		0	0
Allowance for loan losses, recoveries		23	21
Provision for loan losses		233	(1)
Allowance for loan losses, ending balance		4,131	3,528
Construction, land and land development [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		2,375	2,384
Allowance for loan losses, charge-offs		0	0
Allowance for loan losses, recoveries		0	0
Provision for loan losses		220	213
Allowance for loan losses, ending balance		2,595	2,597
1-4 family residential first mortgages [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		216	250
Allowance for loan losses, charge-offs		0	0
Allowance for loan losses, recoveries		70	3
Provision for loan losses		(39)	(17)
Allowance for loan losses, ending balance		247	236
Home equity [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		127	171
Allowance for loan losses, charge-offs		(1)	0
Allowance for loan losses, recoveries		1	20
Provision for loan losses		0	(29)
Allowance for loan losses, ending balance		127	162
Commercial real estate [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		10,565	10,301
Allowance for loan losses, charge-offs		0	0
Allowance for loan losses, recoveries		3	4
Provision for loan losses		586	(176)
Allowance for loan losses, ending balance		11,154	10,129
Consumer and other [Member]
Loans, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, beginning balance		77	75
Allowance for loan losses, charge-offs		0	0
Allowance for loan losses, recoveries		1	0
Provision for loan losses		0	10
Allowance for loan losses, ending balance		$ 78	$ 85

[1] The negative provisions for the various segments are related to the decline in outstanding balances in each of those portfolio segments during the time periods disclosed and/or improvement in the credit quality factors related to those portfolio segments.