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, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (41,056)	$ 126,008	$ (146,937)	$ 558,626
Net Premiums Earned On Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	7,100	10,300	23,000	31,700
Financial Guaranty Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	(51,800)	120,100	(171,200)	536,600
Financial Guaranty VIE Derivative Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	3,700	(4,500)	1,300	(9,400)
Net Interest Margin Securities Related And Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	0	100	0	(300)
Radian Group Consolidated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (41,000)	$ 126,000	$ (146,900)	$ 558,600