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	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) consecutivePayment	Jun. 30, 2019	Dec. 31, 2019 USD ($) consecutivePayment
Collateral dependent loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value | $	$ 7,959
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 | $	$ 14,160		$ 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	(0.086)		(0.087)
Minimum | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.106)		(0.102)
Minimum | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.000)		(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	100.00%
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	(0.087)		(0.090)
Maximum | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.204)		(0.198)
Maximum | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.024)		(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	16.80%
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	(0.086)		(0.087)
Weighted Average | Mortgage servicing rights | Measurement Input, Constant Prepayment Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.127)		(0.122)
Weighted Average | Mortgage servicing rights | Measurement Input, Default Rate
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Unobservable inputs	(0.007)		(0.007)