Servicing Rights - Key Assumptions and the Sensitivity of the Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 678,096	$ 659,048
Base
Servicing rights	$ 11,653	$ 11,920
MSR as a percentage of serviced loans (percent)	1.72%	1.81%
Mortgage servicing rights
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 678,096	$ 659,048
Weighted average rate of note (percent)	3.88%	3.90%
Base
Constant prepayment rate (percent)	12.14%	10.61%
Discount rate (percent)	8.25%	8.52%
Servicing rights	$ 11,653	$ 11,920	$ 11,254	$ 10,821
MSR as a percentage of serviced loans (percent)	1.72%	1.81%
1.0% Adverse Rate Change
Constant prepayment rate (percent)	30.71%	26.25%
Discount rate (percent)	7.25%	7.52%
Fair value MSR	$ 6,303	$ 7,005
Percentage of MSR (percent)	0.93%	1.06%
2.0% Adverse Rate Change
Constant prepayment rate (percent)	33.44%	28.39%
Discount rate (percent)	6.25%	6.52%
Fair value MSR	$ 5,904	$ 6,625
Percentage of MSR (percent)	0.87%	1.01%