Note 9 - Reinsurance Reinsurance Text (Details) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended			12 Months Ended			12 Months Ended						1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jan. 24, 2012 January 2012 Assured Guaranty Ceded Public Finance Transaction [Member] Radian Asset Assurance [Member]	Dec. 31, 2012 Initial Quota Share Reinsurance Transaction [Member]	Dec. 31, 2012 Initial Quota Share Reinsurance Transaction [Member] Maximum [Member]	Dec. 31, 2012 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2012 Initial Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Maximum [Member] Conventional Mortgage Loan [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Conventional Mortgage Loan [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Non Conventional Mortgage Loan [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Minimum [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Maximum [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Radian Guaranty [Member] Minimum [Member]	Dec. 31, 2012 Second Quota Share Reinsurance Transaction [Member] Scenario, Forecast [Member] Radian Guaranty [Member] Maximum [Member]	Jan. 24, 2012 January 2012 Assured Guaranty Ceded Public Finance Transaction [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Prepaid Reinsurance Premiums	$ 64,500,000	$ 800,000
Premiums Written, Net, Consolidated [Abstract]
Direct Premiums Written	892,983,000	755,758,000	788,321,000
Assumed Premiums Written	(88,991,000)	(11,162,000)	(6,585,000)
Ceded Premiums Written	(117,362,000)	(37,349,000)	(89,855,000)		(52,200,000)				(9,600,000)
Net premiums written—insurance	686,630,000	707,247,000	691,881,000
Ceded Premiums Earned, Property and Casualty					16,100,000				500,000
Premiums Earned, Net, Property and Casualty [Abstract]
Reinsurance Premiums for Insurance Companies, by Product Segment, Gross Amount	796,253,000	762,428,000	891,167,000
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Assumed from Other Companies	(3,571,000)	32,337,000	29,063,000
Reinsurance Premiums for Insurance Companies, by Product Segment, Amount Ceded to Other Companies	53,700,000	38,740,000	94,497,000
Reinsurance Premiums for Insurance Companies, by Product Segment, Net Amount	738,982,000	756,025,000	825,733,000
First Lien Primary Mortgage Insurance Risk In Force Ceded					1,500,000,000		1,500,000,000		368,400,000				750,000,000	2,000,000,000	750,000,000	2,000,000,000
Percentage of Reinsurance Able To Be Commuted						66.66%				50.00%
Percentage of New Insurance Written To Be Ceded								20.00%
Fees and Commissions					13,000,000				3,400,000
Percentage of Premium and Losses Incurred To Be Ceded											20.00%	100.00%
Ceded Commission Percentage											35.00%	25.00%
Ceded Commission Percentage on Risk in Force Subject to Commutation											30.00%
Assumed Reinsurance Exposure Commuted In January 2012				$ 1,800,000,000													$ 1,800,000,000