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Description of Business - Additional Information (Details) $ in Billions | 6 Months Ended |
--- | --- | ---
Jun. 30, 2025 USD ($) Segment | Dec. 31, 2024 USD ($)
Business Overview [Abstract] |  |
Number of reportable business segments | Segment | 1 |
Mortgage Insurance revenues |  |
Business Overview [Abstract] |  |
Down payment purchase price (percent) | 20.00% |
Equity in home (percent) | 20.00% |
Direct primary mortgage insurance in force | $ 276.7 | $ 275.1
Direct primary mortgage insurance risk in force | $ 72.8 | $ 72.1

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- Definition This element represents the maximum down payment percentage on a home's purchase price that is used to measure the need for private mortgage insurance. + References No definition available. + Details
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- Definition This element represents the maximum equity-ownership percentage on a home's value that is used to measure the need for private mortgage insurance for refinancings. + References No definition available. + Details
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- Definition Risk In Force, Ceded Amount + References No definition available. + Details
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- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 47 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482785/280-10-55-47 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 54 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482785/280-10-55-54 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482810/280-10-50-18 + Details
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- Definition Amount of participating insurance in force. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 50 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479756/944-50-50-1 + Details
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