Loss Reserves (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 loan	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan	Dec. 31, 2021 USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (decrease) in loss reserves			$ (156,344)	$ 55,699
Prior years			(186,582)	$ 1,732
Premium refund liability, expected claim payments	$ 32,800		$ 32,800		$ 37,300
Primary Delinquent Inventory [Roll Forward]
Delinquent inventory at the beginning of period (in loans) | loan	30,462	52,775	33,290	57,710
New notices (in loans) | loan	9,396	9,036	20,099	22,047
Cures (in loans) | loan	(12,677)	(18,460)	(25,877)	(36,088)
Paid claims (in loans) | loan	(319)	(346)	(641)	(658)
Rescissions and denials (in loans) | loan	(7)	(6)	(16)	(12)
Delinquent inventory at end of period (in loans) | loan	26,855	42,999	26,855	42,999
$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			$ 13,000
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			16,000
Increase (decrease) in estimated claim rate on primary defaults
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			(186,163)	$ (356)
Increase (decrease) in estimated severity on primary defaults
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			(9,945)	512
Change in estimates related to pool reserves, LAE reserves, reinsurance, and other
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years			$ 9,526	$ 1,576