Allowance for Loan Losses (the Allowance) - Carrying value based on credit quality indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	$ 1,205,751	$ 911,134
Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	1,124,015	877,264
Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	61,740	16,690
Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	16,316	17,180
Doubtful
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	3,680
Commercial mortgage
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	485,103	362,590
Commercial mortgage | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	449,545	353,724
Commercial mortgage | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	32,059	5,821
Commercial mortgage | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	3,499	3,045
Home equity lines and loans
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	64,987	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	63,923	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	1,064	537
Construction
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	140,246	172,044
Construction | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	132,286	170,823
Construction | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	7,960	1,221
Commercial and industrial, including leases
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	261,750	273,301
Commercial and industrial, including leases | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	227,349	251,320
Commercial and industrial, including leases | Special mention
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	21,721	9,648
Commercial and industrial, including leases | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	9,000	12,333
Commercial and industrial, including leases | Doubtful
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	3,680
Small business loans
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	49,542	21,616
Small business loans | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	46,789	20,351
Small business loans | Substandard
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	2,753	$ 1,265
Paycheck Protection Program loans
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	203,543
Paycheck Protection Program loans | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	203,543
MainStreet Lending Program Loans
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	580
MainStreet Lending Program Loans | Pass
Loans and Leases by Credit Ratings
Carry value of loans and leases excluding residential mortgage, consumer and leases	$ 580