Loss Reserves - Prior Year Loss Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years	$ (60,015)	$ 19,604	$ (71,006)
(Decrease) in estimated claim rate on primary delinquencies
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years	(82,904)	(2,536)	(111,848)
Increase (decrease)in estimated claim severity on primary delinquencies
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years	310	13,535	(434)
Change in estimates related to pool reserves, LAE reserves, reinsurance and other
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior years	$ 22,579	$ 8,605	$ 41,276