Note 13 - Statutory Information Statutory Information (Details) (USD $)		9 Months Ended		12 Months Ended		1 Months Ended		9 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Radian Guaranty [Member]		Dec. 31, 2012 Radian Guaranty [Member]		Jul. 31, 2013 Radian Asset Assurance [Member]	Sep. 30, 2013 Radian Asset Assurance [Member]	Sep. 30, 2013 Parent Company	Sep. 30, 2013 State Insurance Regulations [Member] Mortgage Insurance Segment state	Sep. 30, 2013 Primary Mortgage Product [Member] Mortgage Insurance Segment Radian Guaranty [Member]	Sep. 30, 2013 Corporate Expenses and Interest Payments Due Within Twelve Months [Member] Parent Company
Statutory Accounting Practices [Line Items]
Number Of States That Have A Statutory Or Regulatory Risk Based Capital Requirement									16
Risk To Capital Ratio, Regulatory Maximum									0.25
Percentage of New Insurance Written Attributable To States With Statutory Or Regulatory Risk Based Capital Requirements										55.40%
Unrestricted Cash and Liquid Investments								$ 822,100,000
Statutory net income (loss)		10,700,000		(175,900,000)
Statutory Accounting Practices, Statutory Capital and Surplus, Balance		1,239,100,000		926,000,000			1,200,000,000
Contingency Reserve		17,200,000		0
Statutory Accounting Practices, Statutory Policyholders' Surplus Plus Contingency Reserves		1,256,300,000		926,000,000
Net Risk In Force		24,899,400,000	[1]	19,226,700,000	[1]
Risk To Capital Ratio		0.198		0.208
Risk to Capital, Entity's Intended Maximum		0.20
Capital Contributions		230,000,000
Claims Paying Resources							1,600,000,000
Payment of Dividend by Subsidiary to Parent						36,000,000
Restricted Cash and Cash Equivalents	1,300,000,000
Proceeds from Contributions from Affiliates								119,500,000			75,500,000
Unrestricted Cash and Liquid Investments Net of Subsidiaries Prepaid Corporate Expenses								$ 702,600,000

[1] RIF, net excludes risk ceded through reinsurance contracts and RIF on defaulted loans.