Note 7 - Reinsurance Quota Share Reinsurance Transactions (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Sep. 30, 2012 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Sep. 30, 2013 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Sep. 30, 2012 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Jun. 30, 2012 Initial Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Sep. 30, 2013 Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Sep. 30, 2013 Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2012 Minimum [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2012 Maximum [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2014 Scenario, Forecast [Member] Initial Quota Share Reinsurance Transaction [Member]	Dec. 31, 2015 Scenario, Forecast [Member] Second Quota Share Reinsurance Transaction [Member]	Apr. 02, 2013 Conventional Mortgage Loan [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Mar. 31, 2013 Conventional Mortgage Loan [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2012 Conventional Mortgage Loan [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]	Dec. 31, 2012 Non Conventional Mortgage Loan [Member] Second Quota Share Reinsurance Transaction [Member] Radian Guaranty [Member]
Reinsurance Transaction Details [Line Items]
Percentage of New Insurance Written To Be Ceded									20.00%
First Lien Primary Mortgage Insurance Risk In Force Ceded					$ 1,400,000,000		$ 1,400,000,000			$ 1,200,000,000	$ 1,200,000,000	$ 750,000,000	$ 2,000,000,000
Percentage of Reinsurance Able To Be Commuted														67.00%	50.00%
Percentage of Premium and Losses Incurred To Be Ceded																5.00%	20.00%	20.00%	100.00%
Ceding Commission Percentage																		35.00%	25.00%
Ceded Commission Percentage Charged on Ceded Risk in Force in the Event of Unexercised Commutation Option																		30.00%
Ceded Premiums Written	17,918,000	21,891,000	64,195,000	91,867,000	5,551,000	16,378,000	17,573,000	41,855,000		8,233,000	32,253,000
Ceded Premiums Earned					7,216,000	5,291,000	22,711,000	8,389,000		5,099,000	12,220,000
Fees and Commissions					$ 1,388,000	$ 4,095,000	$ 4,393,000	$ 10,464,000		$ 2,882,000	$ 11,289,000