Losses and LAE - Narrative (Details)	12 Months Ended
Dec. 31, 2022 default payment	Dec. 31, 2021 default	Dec. 31, 2020 default
Number of payments missed for insured loans	2
Minimum
Number of payments missed for insured loans	2
Mortgage \| TEXAS \| New Insurance Written \| Geographic Concentration Risk
Concentration risk, percentage	12.00%
Mortgage \| CALIFORNIA \| New Insurance Written \| Geographic Concentration Risk
Concentration risk, percentage		10.90%	10.40%
Primary Mortgage Product \| Mortgage
Number of new primary default notices \| default	37,738	37,470	108,025
Default to claim rate assumption percentage	8.00%	8.00%	8.50%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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