Loans and Allowance - Non-accrual loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	$ 1,947	$ 3,270
Transfer into non-accrual	4,240	3,494
Transfer to OREO		(705)
Loans paid down/payoffs	(1,268)	(3,235)
Loans return to accrual status	(221)	(448)
Loans charged off	(571)	(1,134)
Balance	4,127	1,947
Consumer
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	186	185
Transfer into non-accrual	135	290
Loans paid down/payoffs	(55)	(27)
Loans return to accrual status	(88)	(58)
Loans charged off	(41)	(204)
Balance	137	186
Residential Real estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	956	2,124
Transfer into non-accrual	571	246
Loans paid down/payoffs	(782)	(633)
Loans return to accrual status		(192)
Loans charged off	(17)	(589)
Balance	728	956
Indirect
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	116	88
Transfer into non-accrual	702	636
Loans paid down/payoffs	(76)	(132)
Loans return to accrual status	(133)	(135)
Loans charged off	(486)	(341)
Balance	123	116
Commercial Mortgage Portfolio Segment
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	27	48
Transfer into non-accrual	86	27
Loans paid down/payoffs	(86)	(48)
Loans charged off	(27)
Balance		27
Construction
Financing Receivable Nonaccrual Status [Roll Forward]
Balance		318
Loans paid down/payoffs		(318)
Commercial Real Estate
Financing Receivable Nonaccrual Status [Roll Forward]
Balance	662	507
Transfer into non-accrual	2,746	2,295
Loans paid down/payoffs	(269)	(2,077)
Loans return to accrual status		(63)
Balance	$ 3,139	$ 662