Fair Value - Assets and Liabilities Measured on a Non-Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Impaired loans
Total impaired loans	$ 17,501	$ 106
Mortgage servicing rights	13,477	273
Commercial Real Estate [Member]
Impaired loans
Total impaired loans	6,342	68
Commercial [Member]
Impaired loans
Total impaired loans	11,159	38
Fair Value, Inputs, Level 2 [Member]
Impaired loans
Mortgage servicing rights	13,477	273
Fair Value, Inputs, Level 3 [Member]
Impaired loans
Total impaired loans	17,501	106
Fair Value, Inputs, Level 3 [Member] | Commercial Real Estate [Member]
Impaired loans
Total impaired loans	6,342	68
Fair Value, Inputs, Level 3 [Member] | Commercial [Member]
Impaired loans
Total impaired loans	$ 11,159	$ 38