Losses and LAE - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 default payment	Dec. 31, 2022 default	Dec. 31, 2021 default
Number of payments missed for insured loans | payment	2
Mortgage Insurance | TEXAS | Primary Risk In Force | Geographic Concentration Risk
Concentration risk, percentage	10.00%
Mortgage Insurance | TEXAS | New Insurance Written | Geographic Concentration Risk
Concentration risk, percentage	13.00%	12.00%	11.00%
Primary Mortgage Product | Mortgage Insurance
Number of new primary default notices | default	44,007	37,738	37,470
Default to claim rate assumption percentage	8.00%	8.00%	8.00%