Loss Reserves (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) loan	Mar. 31, 2022 USD ($) loan	Dec. 31, 2022 USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves	$ 527	$ (32,250)
Losses incurred related to current year notices	47,212	36,344
Losses incurred related to prior year notices	(40,766)	$ (55,658)
Premium refund liability, expected claim payments	$ 24,200		$ 25,500
Primary Delinquent Inventory [Roll Forward]
Delinquent inventory at the beginning of period (in loans) | loan	26,387	33,290
New notices (in loans) | loan	11,297	10,703
Cures (in loans) | loan	(12,607)	(13,200)
Paid claims (in loans) | loan	(311)	(322)
Rescissions and denials (in loans) | loan	(9)	(9)
Delinquent inventory at end of period (in loans) | loan	24,757	30,462
$1,000 Increase/Decrease In Average Severity Reserve Factor
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves	$ 9,000
One Percentage Point Increase/Decrease In Average Claim Rate Reserve Factor
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves	15,000
Increase (decrease) in estimated claim rate on primary defaults
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Losses incurred related to prior year notices	(43,431)	$ (55,777)
Change in estimates related to severity on primary defaults, pool reserves, LAE reserves, reinsurance, and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Losses incurred related to prior year notices	$ 2,665	$ 119