Schedule II - Financial Information of Registrant - Parent Company Only Supplemental Notes - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2025 USD ($) FinancialGuarantyStructuredTransaction	Sep. 30, 2025 USD ($)	Dec. 31, 2025 USD ($) FinancialGuarantyStructuredTransaction	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($) FinancialGuarantyStructuredTransaction	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Condensed Financial Statements, Captions [Line Items]
Net deferred tax liability	$ 942,193		$ 942,193		$ 942,193	$ 772,232
Proceeds from intercompany notes borrowings	$ 600,000	$ 600,000			$ 600,000
Debt instrument term		10 years			10 years
Bear interest rate	6.50%		6.50%		6.50%
Return of capital				$ 200,000
Net operating loss expiration date					2027
Radian Guaranty
Condensed Financial Statements, Captions [Line Items]
Statutory policyholders' surplus	$ 646,115		$ 646,115		$ 646,115	722,861	$ 619,584
Return of capital				$ 200,000
Payments of ordinary dividends					$ 595,000
Radian Guaranty | Indirect Guarantee of Indebtedness
Condensed Financial Statements, Captions [Line Items]
Number of guaranteed structured transactions for Radian Guaranty | FinancialGuarantyStructuredTransaction	2		2		2
Guarantor obligations, aggregate remaining credit exposure	$ 46,000		$ 46,000		$ 46,000
Radian Title Insurance
Condensed Financial Statements, Captions [Line Items]
Return of capital			35,000		35,000
Radian Investment Group Inc.
Condensed Financial Statements, Captions [Line Items]
Return of capital					27,000
Radian Mortgage Assurance
Condensed Financial Statements, Captions [Line Items]
Statutory accounting practices, statutory capital and surplus required	5,000		5,000		5,000
Statutory policyholders' surplus	9,000		9,000		9,000
RIF	0		0		0
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net deferred tax liability	$ 270,345		$ 270,345		270,345	245,692
Investments in and advances to affiliates, at fair value, period increase (decrease)					$ 37,000	$ 76,000