Note 7 - Reinsurance Reinsurance Transactions (Details) - Reinsurer Concentration Risk [Member] - Radian Guaranty $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended	15 Months Ended	24 Months Ended	33 Months Ended
		Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015	Mar. 31, 2013	Dec. 31, 2017 USD ($)	Dec. 31, 2015	Dec. 31, 2012 transaction
Quota Share Reinsurance Transactions [Member]
Ceded Credit Risk [Line Items]
Number of Quota Share Reinsurance Agreements | transaction										2
Ceded Insurance Commission Percentage				30.00%		35.00%
Ceded Premiums Written	[1]	$ 7,356	$ 4,217	$ 15,318	$ 14,813
Ceded Premiums Earned	[1]	11,172	9,463	22,497	24,249
Accrued Liabilities for Commissions, Expense and Taxes		2,099	2,982	4,369	6,147
Fees and Commissions		4,976	5,363	10,715	12,027
First Lien Primary Mortgage Insurance Risk In Force Ceded		$ 1,900,000	$ 2,400,000	1,900,000	$ 2,400,000
Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Ceded Insurance Commission Percentage		25.00%
Percentage of NIW Able to be Ceded under QSA							20.00%		35.00%
Ceded Premiums Written	[1]	$ 11,488		209,081
Ceded Premiums Earned	[1]	7,146		13,140
Accrued Liabilities for Commissions, Expense and Taxes		4,844		55,776
Fees and Commissions		3,759		6,791
First Lien Primary Mortgage Insurance Risk In Force Ceded		$ 3,500,000		$ 3,500,000
Scenario, Forecast [Member] | Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Percentage of NIW Able to be Ceded under QSA								35.00%
Maximum [Member] | Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Loss Ratio		55.00%
Maximum [Member] | Scenario, Forecast [Member] | Single Premium QSR Transaction [Member]
Ceded Credit Risk [Line Items]
Ceded Premiums Written								$ 195,000

[1] Net of profit commission.