Note 9 - Losses and LAE Rescissions And Denials (Details) - USD ($) $ in Thousands		3 Months Ended
	Aug. 29, 2017	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Rescissions And Denials [Line Items]
Reserve for losses and loss adjustment expense (“LAE”) (Note 9)		$ 891,348		$ 976,399
2013 Freddie Mac Agreement [Member]
Rescissions And Denials [Line Items]
Reserve for losses and loss adjustment expense (“LAE”) (Note 9)		57,300
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Rescissions And Denials [Line Items]
Restricted Investments Held as Collateral for Master Transaction Agreement, Net		75,300		74,700
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member] | Maximum [Member] | Scenario, Forecast [Member]
Rescissions And Denials [Line Items]
Not Final Loss Mitigation Activity	$ 74,000
Mortgage Insurance Segment
Rescissions And Denials [Line Items]
Claim Rescissions And Denials, Net of Reinstatements		5,600	$ (14,700)
Decrease To Our Loss Reserves Due To Estimated Rescissions And Denials		67,000		69,000
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount		22,800		26,600
Reserve for losses and loss adjustment expense (“LAE”) (Note 9)		$ 891,348	$ 1,384,714	$ 976,399	$ 1,560,032