Note 8 - Reinsurance Reinsurance Premiums (Details) - USD ($) $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2016		Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015		Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014		Jun. 30, 2012
Premiums Earned, Net [Abstract]
Direct Premiums Earned																		$ 999,093		$ 973,645		$ 905,502
Assumed Premiums Earned																		35		43		43
Ceded Premiums Earned																		(77,359)		(57,780)		(61,017)
Net premiums earned—insurance		$ 233,585	[1]	$ 238,149		$ 229,085		$ 220,950		$ 226,443	[1]	$ 227,433		$ 237,437		$ 224,595		921,769		$ 915,908	[1]	$ 844,528
Radian Guaranty [Member] | Initial Quota Share Reinsurance Transaction [Member] | Reinsurer Concentration Risk [Member]
Premiums Earned, Net [Abstract]
Percentage of New Insurance Written To Be Ceded																								20.00%
First Lien Primary Mortgage Insurance Risk In Force Ceded		600,000																600,000
Profit Commission Earned on Ceded Risk																		9,200
Unearned Ceding Commissions		15,000																$ 15,000
Prepaid Reinsurance Commissions, Amortization Period																		5 years
Ceded Insurance Commission Percentage																				20.00%		25.00%
Radian Guaranty [Member] | Initial Quota Share Reinsurance Transaction [Member] | Reinsurer Concentration Risk [Member] | Maximum [Member]
Premiums Earned, Net [Abstract]
First Lien Primary Mortgage Insurance Risk In Force Ceded																								$ 1,600,000
Radian Guaranty [Member] | Second Quota Share Reinsurance Transaction [Member] | Reinsurer Concentration Risk [Member]
Premiums Earned, Net [Abstract]
First Lien Primary Mortgage Insurance Risk In Force Ceded		1,000,000																$ 1,000,000
Profit Commission Earned on Ceded Risk																		8,300
Unearned Ceding Commissions		$ 8,500																8,500
Radian Guaranty [Member] | Second Quota Share Reinsurance Transaction [Member] | Reinsurer Concentration Risk [Member] | Maximum [Member]
Premiums Earned, Net [Abstract]
First Lien Primary Mortgage Insurance Risk In Force Ceded										$ 1,600,000										$ 1,600,000
Mortgage Insurance Segment
Premiums Written, Net [Abstract]
Direct Premiums Written																		1,000,111		1,009,409		$ 982,976
Assumed Premiums Written																		29		104		(882)
Ceded Premiums Written	[2]																	(266,306)		(41,008)		(56,913)
Net premiums written—insurance																		733,834	[3],[4]	968,505	[5],[6]	925,181	[7],[8]
Premiums Earned, Net [Abstract]
Direct Premiums Earned																		999,093		973,645		905,502
Assumed Premiums Earned																		35		43		43
Ceded Premiums Earned	[2]																	(77,359)		(57,780)		(61,017)
Net premiums earned—insurance																		$ 921,769	[4]	$ 915,908	[6]	$ 844,528	[8]

[1] For all periods presented, reflects changes to align our segment reporting structure with recent changes in personnel reporting lines and management oversight related to contract underwriting performed on behalf of third parties. Revenue and expenses for this business are now reflected in the Services segment. As a result, for all periods presented, Services revenue and cost of services have increased, with offsetting reductions in other operating expenses.

[2] Net of profit commission.

[3] Net of ceded premiums written under the QSR Transactions and the Single Premium QSR Transaction. See Note 8 for additional information.

[4] Reflects changes to align our segment reporting structure with recent changes in personnel reporting lines and management oversight related to contract underwriting performed on behalf of third parties. Revenue and expenses for this business are now reflected in the Services segment. As a result, for all periods presented, Services revenue, cost of services and other operating expenses have increased, with offsetting reductions in Mortgage Insurance other income and other operating expenses.

[5] Net of ceded premiums written under the QSR Transactions. See Note 8 for additional information.

[6] Reflects changes to align our segment reporting structure with recent changes in personnel reporting lines and management oversight related to contract underwriting performed on behalf of third parties. Revenue and expenses for this business are now reflected in the Services segment. As a result, for all periods presented, Services revenue, cost of services and other operating expenses have increased, with offsetting reductions in Mortgage Insurance other income and other operating expenses.

[7] Net of ceded premiums written under the QSR Transactions. See Note 8 for additional information.

[8] Reflects changes to align our segment reporting structure with recent changes in personnel reporting lines and management oversight related to contract underwriting performed on behalf of third parties. Revenue and expenses for this business are now reflected in the Services segment. As a result, for all periods presented, Services revenue, cost of services and other operating expenses have increased, with offsetting reductions in Mortgage Insurance other income and other operating expenses.