Note 3 - Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Income (Loss) from Continuing Operations Attributable to Parent										$ 74,528		$ 70,091		$ 45,193		$ 91,727		$ 308,253		$ 281,539	[1]	$ 1,259,574
Income (Loss) From Continuing Operations, Diluted, Amount																		314,069		296,297		1,273,946
Less: Income (loss) from discontinued operations, net of tax										$ 0	[2]	$ 0	[2]	$ 4,855	[2]	$ 530	[2]	0		5,385	[1],[2]	(300,057)
Net Income (Loss) Available to Common Stockholders, Basic																		308,253		286,924		959,517
Net Income (Loss) Available to Common Stockholders, Diluted																		$ 314,069		$ 301,682		$ 973,889
Average common shares outstanding																		211,789		199,910		184,551
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	[3]																	2,999		2,393		3,150
Adjusted shares outstanding-diluted		224,776		225,968		226,203		239,707		247,981		250,795		246,650		243,048		229,258	[1]	246,332	[1]	233,902
Net income (loss) from continuing operations, per basic share																		$ 1.46		$ 1.41		$ 6.83
Net income (loss) from discontinued operations, per basic share																		0.00		0.03		(1.63)
Net (loss) income per share—basic																		1.46		1.44		5.20
Net income (loss) from continuing operations, per diluted share																		1.37		1.20		5.44
Net income (loss) from discontinued operations and disposal of discontinued operations, net of tax, per diluted share																		0.00		0.02		(1.28)
Net (loss) income per share—diluted		$ 0.27	[4]	$ 0.37	[4]	$ 0.44	[4]	$ 0.29	[4]	$ 0.32	[4]	$ 0.29	[4]	$ 0.22	[4]	$ 0.39	[4]	$ 1.37	[1],[4]	$ 1.22	[1],[4]	$ 4.16
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount																		1,042		728		542
Convertible Debt [Member] | Convertible Senior Notes Due 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	[3]																	207		6,293		8,465
Convertible Debt [Member] | Convertible Senior Notes Due 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest on Convertible Debt, Net of Tax	[5]																	$ 5,816		$ 14,758		$ 14,372
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities																		14,263		37,736		37,736

[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] Radian completed the sale of Radian Asset Assurance to Assured on April 1, 2015, pursuant to the Radian Asset Assurance Stock Purchase Agreement. Until the April 1, 2015 sale date, the operating results of Radian Asset Assurance were classified as discontinued operations for all periods presented in our consolidated statements of operations. See Note 18 for additional information.

[3] The following number of shares of our common stock equivalents issued under our stock-based compensation arrangements and convertible debt, if any, were not included in the calculation of diluted net income per share because they were anti-dilutive: Year Ended December 31,(in thousands)2016 2015 2014Shares of common stock equivalents1,042 728 542

[4] Diluted net income per share is computed independently for each period presented. Consequently, the sum of the quarters may not equal the total net income per share for the year. For all calculations, the determination of whether potential common shares are dilutive or anti-dilutive is based on net income from continuing operations.

[5] As applicable, includes coupon interest, amortization of discount and fees, and other changes in income or loss that would result from the assumed conversion.