Note 3 - Derivative Instruments Change in Fair Value of Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ 10,778	$ (41,056)	$ (70,357)	$ (146,937)
Net Premiums Earned On Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	4,170	7,169	14,019	23,041
Financial Guaranty Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	9,198	(51,839)	(86,233)	(171,219)
Financial Guaranty VIE Derivative Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	(4,026)	3,616	513	1,253
Net Interest Margin Securities Related And Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	1,436	(2)	1,344	(12)
Radian Group Consolidated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ 10,778	$ (41,056)	$ (70,357)	$ (146,937)