Schedule II Financial Information of Registrant - Parent Company Only Supplemental Notes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) transaction	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Condensed Financial Statements, Captions [Line Items]
Net deferred tax liability (Note A)	$ 337,509	$ 213,897
Allocated operating expenses	147,386	129,870	$ 124,412
Allocated interest expense	82,833	68,938	53,692
Radian Mortgage Assurance
Condensed Financial Statements, Captions [Line Items]
Statutory accounting practices, statutory capital and surplus required	5,000
Statutory policyholders’ surplus	9,000
RIF	0
Radian Guaranty
Condensed Financial Statements, Captions [Line Items]
Statutory policyholders’ surplus	$ 778,148	481,484	637,718
Radian Guaranty | Indirect Guarantee of Indebtedness
Condensed Financial Statements, Captions [Line Items]
Number of guaranteed structured transactions for radian guaranty | transaction	2
Guarantor obligations, maximum exposure, undiscounted	$ 63,300
Parent Company
Condensed Financial Statements, Captions [Line Items]
Net deferred tax liability (Note A)	283,585	272,868
Total allocated expenses	230,219	$ 198,808	$ 178,104
Investments in and advances to affiliates, at fair value, period increase (decrease)	$ 48,500