Note 10 - Losses and LAE Rescissions And Denials (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Rescissions And Denials [Line Items]
Reserve for losses and loss adjustment expense (“LAE”) (Note 10)	$ 556,488	$ 760,269
Mortgage Insurance Segment
Rescissions And Denials [Line Items]
Default To Claim Rate Estimate, Gross, For New Defaults	10.50%	12.00%	12.00%
Decrease To Our Loss Reserves Due To Estimated Rescissions And Denials	$ 23,000	$ 39,000
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	24,800	14,300
Reserve for losses and loss adjustment expense (“LAE”) (Note 10)	556,488	760,269	$ 821,934	$ 976,399
2013 Freddie Mac Agreement [Member]
Rescissions And Denials [Line Items]
Reserve for losses and loss adjustment expense (“LAE”) (Note 10)	2,800
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Rescissions And Denials [Line Items]
Marketable Securities, Restricted	$ 5,500	$ 63,900