Note 3 - Derivative Instruments Change in Fair Value of Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (167,670)	$ (72,757)
Net Premiums Earned On Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	4,992	8,648
Financial Guaranty Credit Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	(175,724)	(80,219)
Financial Guaranty VIE Derivative Liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	3,062	(1,227)
Net Interest Margin Securities Related And Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	0	41
Radian Group Consolidated [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative instruments	$ (167,670)	$ (72,757)