Loss Reserves - Prior Year Loss Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for Claims and Claims Adjustment Expense [Line Items]
Total prior year loss development	$ (208,514)	$ (404,130)	$ (60,015)
Increase (decrease) in estimated claim rate on primary defaults
Liability for Claims and Claims Adjustment Expense [Line Items]
Total prior year loss development	(200,983)	(400,577)	(82,904)
Change in estimates related to severity on primary defaults, pool reserves, LAE reserves, reinsurance, and other
Liability for Claims and Claims Adjustment Expense [Line Items]
Total prior year loss development	$ (7,531)	$ (3,553)	$ 22,889