Fair Value of Assets and Liabilities - Nonrecurring Basis (Details) - Non recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair value, assets and liabilities measured on recurring and non recurring basis
Impaired loans	$ 5,301	$ 4,816
Foreclosed assets	10	8
Servicing rights	2,579	3,845
Loans held for sale
Fair value, assets and liabilities measured on recurring and non recurring basis
Loans held for sale	111,311	46,846
Impaired loans
Fair value, assets and liabilities measured on recurring and non recurring basis
Net impairment	407	3,138
Level 2 | Loans held for sale
Fair value, assets and liabilities measured on recurring and non recurring basis
Loans held for sale	111,311	46,846
Level 3
Fair value, assets and liabilities measured on recurring and non recurring basis
Impaired loans	5,301	4,816
Foreclosed assets	10	8
Servicing rights	$ 2,579	$ 3,845