Note 12 - Statutory Information Statutory Information (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Radian Guaranty [Member]
Statutory Accounting Practices [Line Items]
Statutory net loss	$ (73,600,000)	$ (545,100,000)
Statutory surplus	919,900,000	843,200,000
Radian Asset Assurance
Statutory Accounting Practices [Line Items]
Statutory surplus	1,100,000,000
Additional Risk And Capital Information
Claims Paying Resources	2,000,000,000
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	53,400,000
CMAC Of Texas
Statutory Accounting Practices [Line Items]
Statutory net loss	(2,200,000)
Statutory surplus	24,000,000
Additional Risk And Capital Information
Required statutory surplus	$ 20,000,000