Loans and Allowance - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	$ 2,066,000	$ 2,541,000	$ 2,541,000
Charged off	(125,000)	(205,000)	(616,000)
Recoveries	57,000		256,000
Provision for loan losses	(80,000)	173,000	(115,000)
Balance, end of year	1,918,000		2,066,000
Individually evaluated for impairment:
Individually evaluated for impairment, Balance in allowance	11,000		15,000
Individually evaluated for impairment, Related loan balance	4,330,000		4,397,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	1,907,000		2,051,000
Collectively evaluated for impairment, Related loan balance	272,630,000		280,341,000
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	122,000	161,000	161,000
Charged off			(69,000)
Recoveries	4,000		16,000
Provision for loan losses	(4,000)		14,000
Balance, end of year	122,000		122,000
Individually evaluated for impairment:
Individually evaluated for impairment, Balance in allowance	11,000		15,000
Individually evaluated for impairment, Related loan balance	86,000		86,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	111,000		107,000
Collectively evaluated for impairment, Related loan balance	12,614,000		11,990,000
Residential Real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	589,000	864,000	864,000
Charged off			(16,000)
Recoveries	3,000		5,000
Provision for loan losses	(45,000)		(264,000)
Balance, end of year	547,000		589,000
Individually evaluated for impairment:
Individually evaluated for impairment, Related loan balance	617,000		631,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	547,000		589,000
Collectively evaluated for impairment, Related loan balance	80,165,000		80,402,000
Indirect
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	917,000	988,000	988,000
Charged off	(125,000)		(504,000)
Recoveries	30,000		225,000
Provision for loan losses	20,000		208,000
Balance, end of year	842,000		917,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	842,000		917,000
Collectively evaluated for impairment, Related loan balance	95,093,000		102,384,000
Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	38,000	241,000	241,000
Charged off			(27,000)
Recoveries	20,000		10,000
Provision for loan losses	(21,000)		(186,000)
Balance, end of year	37,000		38,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	37,000		38,000
Collectively evaluated for impairment, Related loan balance	13,172,000		11,907,000
Construction
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	11,000	4,000	4,000
Provision for loan losses	(2,000)		7,000
Balance, end of year	9,000		11,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	9,000		11,000
Collectively evaluated for impairment, Related loan balance	2,563,000		3,317,000
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of year	389,000	$ 283,000	283,000
Provision for loan losses	(28,000)		106,000
Balance, end of year	361,000		389,000
Individually evaluated for impairment:
Individually evaluated for impairment, Related loan balance	3,627,000		3,680,000
Collectively evaluated for impairment:
Collectively evaluated for impairment, Balance in allowance	361,000		389,000
Collectively evaluated for impairment, Related loan balance	$ 69,023,000		$ 70,341,000