Fair Value of Assets and Liabilities - Valuation Technique (Details) - Level 3	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Loans held for branch sale
Valuation techniques and significant unobservable inputs
Loans held for sale		$ 32,031,000
Loans Held-for-sale, Valuation Technique [Extensible List]		us-gaap:ValuationTechniqueDiscountedCashFlowMember
Loans Held-for-sale, Measurement Input [Extensible List]		us-gaap:MeasurementInputCostToSellMember
Impaired loans | Appraisal value | Property specific adjustment
Valuation techniques and significant unobservable inputs
Impaired loans	$ 4,816,000	$ 4,022,000
Foreclosed assets | Appraisal value | Property specific adjustment
Valuation techniques and significant unobservable inputs
Foreclosed assets	8,000	84,000
Servicing rights
Valuation techniques and significant unobservable inputs
Servicing rights	$ 3,845,000	$ 4,623,000
Servicing Asset, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Servicing rights | Prepayment speed assumptions | Minimum
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	123	104
Servicing rights | Prepayment speed assumptions | Maximum
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	267	211
Servicing rights | Prepayment speed assumptions | Weighted average
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	194	130
Servicing rights | Discount rate
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	0.094	0.105
Servicing rights | Discount rate | Weighted average
Valuation techniques and significant unobservable inputs
Servicing Asset, Measurement Input	0.094	0.105