Servicing Rights - Key Assumptions and the Sensitivity of the Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 659,048	$ 557,583
Base
Mortgage servicing rights, at fair value	$ 11,920	$ 10,821
MSR as a percentage of serviced loans	1.81%	1.94%
Mortgage servicing rights
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 659,048	$ 557,583
Weighted average rate of note	3.90%	3.91%
Base
Constant prepayment rate	10.61%	7.70%
Average discount rate	8.52%	9.94%
Mortgage servicing rights, at fair value	$ 11,920	$ 10,821	$ 7,305	$ 4,157
MSR as a percentage of serviced loans	1.81%	1.94%
1.0% Adverse Rate Change
Constant prepayment rate	26.25%	19.35%
Discount rate	7.52%	8.94%
Fair value MSR	$ 7,005	$ 7,115
Percentage of MSR	1.06%	1.28%
2.0% Adverse Rate Change
Constant prepayment rate	28.39%	20.95%
Discount rate	6.52%	7.94%
Fair value MSR	$ 6,625	$ 6,829
Percentage of MSR	1.01%	1.22%