Servicing Rights - Key Assumptions and the Sensitivity of the Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 682,827	$ 683,117
Base
Percentage of MSR (percent)	1.71%	1.64%
Mortgage servicing rights
Servicing Assets at Fair Value [Line Items]
Aggregate portfolio principal balance	$ 682,827	$ 683,117
Weighted average rate of note (percent)	3.52%	3.62%
Base
Constant prepayment rate (percent)	12.47%	13.05%
Discount rate (percent)	7.75%	7.75%
Fair value MSR	$ 11,657	$ 11,218	$ 11,653	$ 11,920
Percentage of MSR (percent)	1.71%	1.64%
1.0% Adverse Rate Change
Constant prepayment rate (percent)	24.94%	26.11%
Discount rate (percent)	6.75%	6.75%
Fair value MSR	$ 7,973	$ 7,455
Percentage of MSR (percent)	1.17%	1.09%
2.0% Adverse Rate Change
Constant prepayment rate (percent)	37.40%	38.97%
Discount rate (percent)	5.75%	5.75%
Fair value MSR	$ 5,902	$ 5,404
Percentage of MSR (percent)	0.86%	0.79%