Note 15 - Statutory Information Statutory Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Reportable Subsegments [Member]
Statutory Accounting Practices [Line Items]
Restricted Net Assets Held by Consolidated Subsidiaries	$ 3,100.0
Radian Guaranty
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Capital and Surplus, Increase (Decrease)	(175.0)
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	1,167.7	$ 1,349.7
Statutory Accounting Practices, Dividends Paid with Approval of Regulatory Agency	175.0
Radian Reinsurance [Member]
Statutory Accounting Practices [Line Items]
Capital Contributions	175.0
Statutory Accounting Practices, Statutory Capital and Surplus, Increase (Decrease)	175.0
Statutory Accounting Practices, Statutory Capital and Surplus, Balance	$ 321.0	$ 147.6