Disclosures about Fair Value of Assets and Liabilities - Qualitative Information about Unobservable Inputs Used in Recurring and Nonrecurring Level 3 Fair Value Measurements, Other than Goodwill (Details) - Significant Unobservable Inputs (Level 3) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) consecutivePayment	Dec. 31, 2019 USD ($) consecutivePayment
Collateral dependent loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value | $	$ 14,781
Valuation Technique	Collateral based measurement
Unobservable Inputs	Discount to reflect current market conditions and ultimate collectibility
Impaired loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value | $		$ 6,806
Valuation Technique		Collateral based measurement
Unobservable Inputs		Discount to reflect current market conditions and ultimate collectibility
Mortgage servicing rights
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value | $	$ 11,705	$ 14,327
Valuation Technique	Discounted cash flows	Discounted cash flows
Unobservable Inputs	Discount rate,Constant prepayment rate,Probability of default	Discount rate,Constant prepayment rate,Probability of default
Minimum | Collateral dependent loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	0.00%
Minimum | Impaired loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability		0.00%
Minimum | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.078	0.087
Minimum | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.071	0.102
Minimum | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.007	0.001
Maximum | Collateral dependent loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	76.00%
Maximum | Impaired loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability		100.00%
Maximum | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.078	0.090
Maximum | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.173	0.198
Maximum | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.197	0.029
Weighted Average | Collateral dependent loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability	8.60%
Weighted Average | Impaired loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Discount to reflect current market conditions and ultimate collectability		7.40%
Weighted Average | Mortgage servicing rights | Measurement Input, Discount Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.078	0.087
Weighted Average | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.140	0.122
Weighted Average | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	0.019	0.007