Schedule II Financial Information of Registrant Parent Company Only Supplemental Notes (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) transaction	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Condensed Financial Statements, Captions [Line Items]
Total Operating Expenses Allocated to Subsidiaries From Parent Company	$ 124,412	$ 94,815	$ 72,764
Total Interest Expense Allocated to Subsidiaries From Parent Company	53,692	42,195	44,686
Parent Company
Supplemental Notes [Abstract]
Total Operating Expenses and Interest Expense Allocated to Subsidiaries From Parent Company	178,104	137,010	117,450
Deferred Income Tax Liabilities, Net	253,739	243,341
Radian Mortgage Assurance
Supplemental Notes [Abstract]
Statutory Accounting Practices, Statutory Capital and Surplus Required	5,000
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	8,800
Risk In Force	0
Radian Guaranty
Supplemental Notes [Abstract]
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 637,700	814,100	$ 1,201,000
Clayton Group Holdings Inc.
Condensed Financial Statements, Captions [Line Items]
Payments for Capital Contributions to Wholly-Owned Subsidiaries		66,100
Indirect Guarantee of Indebtedness | Radian Guaranty
Supplemental Notes [Abstract]
Number of Guaranteed Structured Transactions For Radian Guaranty | transaction	2
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 79,300
Impairment on Intercompany Interest Receivable | Clayton Group Holdings Inc.
Condensed Financial Statements, Captions [Line Items]
Payments for Capital Contributions to Wholly-Owned Subsidiaries		17,800
Intercompany Receivable | Clayton Group Holdings Inc.
Condensed Financial Statements, Captions [Line Items]
Payments for Capital Contributions to Wholly-Owned Subsidiaries		$ 48,300