Allowance for Loan and Lease Losses (the "Allowance") - Carrying value based on performance status (Details) $ in Thousands	Mar. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($) item
Loans and Leases by Credit Ratings
Troubled debt restructurings	$ 4,153	$ 4,266
Carrying value of residential mortgage, consumer and leases	46,763	43,974
Performing
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	45,906	43,005
Nonperforming
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	857	969
Residential mortgage
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	44,853	41,938
Residential mortgage | Performing
Loans and Leases by Credit Ratings
Troubled debt restructurings	0	0
Carrying value of residential mortgage, consumer and leases	43,996	40,969
Residential mortgage | Nonperforming
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	$ 857	$ 969
Number of loans | item	6	6
Loans receivable, net	$ 1,200	$ 1,900
Consumer
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	751	701
Consumer | Performing
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	751	701
Leases, net
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	1,159	1,335
Leases, net | Performing
Loans and Leases by Credit Ratings
Carrying value of residential mortgage, consumer and leases	$ 1,159	$ 1,335