Allowance for Loan Losses (the Allowance) - Carrying value based on credit quality indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	$ 969,652	$ 911,134
Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	934,299	877,264
Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	18,263	16,690
Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	17,090	17,180
Commercial mortgage | Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	391,328	362,590
Commercial mortgage | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	381,035	353,724
Commercial mortgage | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	7,278	5,821
Commercial mortgage | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	3,015	3,045
Home equity lines and loans | Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	78,764	81,583
Home equity lines and loans | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	78,088	81,046
Home equity lines and loans | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	676	537
Construction | Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	175,364	172,044
Construction | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	174,158	170,823
Construction | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	1,206	1,221
Commercial and industrial | Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	292,423	273,301
Commercial and industrial | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	270,780	251,320
Commercial and industrial | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	9,779	9,648
Commercial and industrial | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	11,864	12,333
Small Business Loans | Evaluated based on credit quality indicators
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	31,773	21,616
Small Business Loans | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	30,238	20,351
Small Business Loans | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	$ 1,535	$ 1,265