Fair Value of Financial Instruments - Nonrecurring Basis (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Mortgage servicing assets, Fair value	$ 552,000	$ 291,000	$ 311,000
Annual cost to service (per loan, in dollars)	$ 75	$ 70
Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Servicing Asset, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Fair Value, Measurements, Nonrecurring
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Mortgage servicing assets, Fair value	$ 452,000
Mortgage servicing assets, Total losses	(16,000)
Fair Value, Measurements, Nonrecurring | Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Mortgage servicing assets, Fair value	$ 452,000
Discount rate | Fair Value, Measurements, Nonrecurring | Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Servicing Asset, Measurement Input	10.25
Annual cost to service (per loan, in dollars) | Fair Value, Measurements, Nonrecurring | Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Servicing Asset, Measurement Input	75,000
Discounted cash flow model | Fair Value, Measurements, Nonrecurring | Level 3 | Mortgage Servicing Assets
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Fair value	$ 452,000
Minimum | Prepayment speed (CPR) | Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Servicing Asset, Measurement Input	9.11
Maximum | Prepayment speed (CPR) | Level 3
Assets Measured at Fair Value on Nonrecurring Basis and Related Losses
Servicing Asset, Measurement Input	13.06