Note 11 - Losses and Loss Adjustment Expenses Rescissions And Denials (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Aug. 29, 2017 USD ($)	Oct. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) percentagepoint	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for Claims and Claims Adjustment Expense			$ 760,269	$ 976,399
2013 Freddie Mac Agreement [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Increase (Decrease) in Restricted Cash and Investments for Operating Activities		$ 11,700
Liability for Claims and Claims Adjustment Expense			57,400
2013 Freddie Mac Agreement [Member] | Radian Guaranty Inc [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Marketable Securities, Restricted			63,900	74,700
Mortgage Insurance Segment
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Decrease To Our Loss Reserves Due To Estimated Rescissions And Denials			39,000	53,000
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount			$ 14,300	26,600
Percentage Point Change In Severity Used In Assumption Shift Analysis | percentagepoint			1
Percentage Point Change In Severity Used In Assumption Shift Analysis | percentagepoint			1
First Lien Primary Claim Severity			101.00%
Impact To Loss Reserves Based On One Percentage Change In Primary Claim Severity			$ 6,300
Impact To Loss Reserves Based On One Percentage Change in Default To Claim Rate			14,500
Liability for Claims and Claims Adjustment Expense			$ 760,269	$ 976,399	$ 1,560,032	$ 2,164,353
Mortgage Insurance Segment | Primary Mortgage Product [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Weighted Average Default To Claim Rate Assumption Net Of Denials And Rescissions			42.00%	46.00%
Mortgage Insurance Segment | Maximum [Member] | Bank of America Settlement Agreement [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Number of Days Delinquent for a Loan to be Considered for Curtailment			90 days
Mortgage Insurance Segment | 2013 Freddie Mac Agreement [Member] | Scenario, Forecast [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Not Final Loss Mitigation Activity	$ 64,000