Note 7 - Reinsurance Reinsurance Transactions (Details) - Reinsurer Concentration Risk [Member] - Radian Guaranty - USD ($) $ in Thousands			3 Months Ended		36 Months Ended
		Dec. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Ceded Premiums Written	[1]		$ 15,791	$ 8,960
Ceded Premiums Earned	[1]		10,377	5,859
Ceding commissions written			6,621	3,712
Ceding Commissions Earned	[2]		5,268	2,937
Ceded losses, net			900	573
Quota Share Reinsurance Transactions [Member]
Ceded Credit Risk [Line Items]
Ceded Premiums Written	[1]		3,931	5,457
Ceded Premiums Earned	[1]		5,612	7,834
Ceding commissions written			1,128	1,559
Ceding Commissions Earned	[2]		3,548	3,894
Ceded losses, net			246	570
2016 Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Concentration Risk, Percentage					35.00%
Risk In Force			6,800,000	3,900,000
2018 Single Premium QSR [Member]
Ceded Credit Risk [Line Items]
Concentration Risk, Percentage		65.00%
Risk In Force			400,000
First Lien Mortgage Insurance Products [Member] | Quota Share Reinsurance Transactions [Member]
Ceded Credit Risk [Line Items]
Risk In Force			$ 1,100,000	$ 1,500,000

[1] Net of profit commission.

[2] Includes amounts reported in policy acquisition costs and other operating expenses.