Loss Reserves - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) Payment loan	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Minimum number of payments past due to be in default | Payment	2
Change in loss reserves (+/-)	$ (325,534)	$ 2,985	$ 325,203
Total prior year loss development	(404,130)	(60,015)	$ 19,604
Premium refund liability, expected claim payments	$ 25,500	$ 37,300
Other items removed from inventory | loan	289	695	0
Prior years	$ 49,626	$ 68,769	$ 109,923
Current year	$ 149,565	$ 124,592	$ 345,170
Pool insurance notice inventory (in number of loans) | loan	391	498	680
Settlements for commutations of coverage, pools of nonperforming loans
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior years	$ 4,600	$ 13,800
$1,000 Increase/Decrease In Average Severity Reserve Factor
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Change in loss reserves (+/-)	10,000
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]
Change in loss reserves (+/-)	15,000
Change in estimates related to IBNR reserves
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Current year	$ 2,300	(5,900)
Probable Loss On Litigation Claims Paying Practices
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total prior year loss development		$ 6,300