Note 10 - Losses and LAE Rescissions And Denials (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Rescissions And Denials [Line Items]
Reserve for losses and loss adjustment expense (“LAE”) (Note 10)	$ 451,542	$ 507,588
Mortgage Insurance Segment
Rescissions And Denials [Line Items]
Default To Claim Rate Estimate, Gross, For New Defaults			11.00%
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	6,200	10,400
Reserve for losses and loss adjustment expense (“LAE”) (Note 10)	$ 448,094	$ 507,588	$ 651,591	$ 760,269
Primary Mortgage Product [Member] | Mortgage Insurance Segment
Rescissions And Denials [Line Items]
Weighted Average Default To Claim Rate Assumption Net Of Denials Rescissions and Reinstatements	35.00%	31.00%