Note 3 - Derivative Instruments Change in Fair Value of Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (33,124)	$ 188,726	$ (105,881)	$ 432,618
Net Premiums Earned On Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	7,300	10,500	15,900	21,400
Financial Guaranty Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	(39,200)	181,900	(119,400)	416,500
Financial Guaranty VIE Derivative Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	(1,200)	(4,000)	(2,400)	(4,900)
Net Interest Margin Securities Related And Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	0	300	0	(400)
Radian Group Consolidated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (33,100)	$ 188,700	$ (105,900)	$ 432,600