Commitments and Contingencies (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) item
Financial instruments whose contract amount represents credit risk [Abstract]
Deposits	$ 690,212,000		$ 661,049,000
Interest income	6,755,000	$ 8,085,000
Noninterest Income	3,025,000	2,260,000
Standby Letters of Credit [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	$ 2,741,000		3,325,000
Letters of credit expiry period	12 months
Letters of credit renewal period	1 year
Current liability for guarantees	$ 9,000		14,000
Home Equity Lines of Credit [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	$ 16,011,000		16,917,000
Loan expiry period	10 years
Unadvanced Construction Commitments [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	$ 74,975,000		79,378,000
Mortgage Loan Commitments [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk			$ 701,000
Number of mortgage loan commitments at fixed interest rate | item			3
Residential mortgage loan commitments	0		$ 701,000
Lines of Credit [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	19,344,000		16,501,000
Loans Sold and Serviced with Limited Repurchase Provisions [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Off-balance sheet credit risk	55,271,000		76,536,000
Repurchases of loans previously sold	$ 0	0
Loans Sold and Serviced with Limited Repurchase Provisions [Member] | Minimum [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Period of delinquency under repurchase agreement	120 days
Loans Sold and Serviced with Limited Repurchase Provisions [Member] | Maximum [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Period of delinquency under repurchase agreement	180 days
Business activities with medical-use cannabis customers [Member] | Cannabis Customers [Member]
Financial instruments whose contract amount represents credit risk [Abstract]
Deposits	$ 31,000,000		22,800,000
Loan balances	$ 18,600,000		$ 14,000,000
Percentage of deposits in total deposits	4.50%		3.40%
Percentage of loans in total loans	2.90%		2.20%
Interest income	$ 155,000	195,000
Noninterest Income	519,000	450,000
Volume of deposits accepted	$ 100,800,000	$ 49,500,000