Schedule II Financial Information of Registrant Parent Company Only Financial Information (Details) $ in Thousands	1 Months Ended			2 Months Ended	3 Months Ended																	10 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	May 31, 2014 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2016 USD ($) transaction		Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	[1]	Jun. 30, 2016 USD ($)	[1]	Mar. 31, 2016 USD ($)	[1]	Dec. 31, 2015 USD ($)		Sep. 30, 2015 USD ($)	[1]	Jun. 30, 2015 USD ($)		Mar. 31, 2015 USD ($)	[1]	Dec. 31, 2013 USD ($)	Dec. 31, 2016 USD ($) transaction	Dec. 31, 2015 USD ($)		Dec. 31, 2014 USD ($)	Aug. 12, 2016 USD ($)	Mar. 31, 2013 USD ($)	Nov. 30, 2010	Nov. 15, 2010 USD ($)
Condensed Financial Statements, Captions [Line Items]
Total Operating Expenses Allocated to Subsidiaries From Parent Company																							$ 56,446	$ 53,738		$ 59,434
Total Interest Expense Allocated to Subsidiaries From Parent Company																							52,092	35,300		33,098
Investments					$ 4,462,430									$ 4,298,686									4,462,430	4,298,686
Fixed-maturities available for sale—at fair value (amortized cost $2,856,468 and $1,893,356)					2,838,512									1,865,461									2,838,512	1,865,461
Short-term investments—at fair value					741,531									1,076,944									741,531	1,076,944
Supplemental Notes [Abstract]
Loss on induced conversion and debt extinguishment (Note 12)					0	[1]		$ (17,397)		$ (2,108)		$ (55,570)		(2,320)	[1]	$ (11)		$ (91,876)	[1]	$ 0			(75,075)	(94,207)	[1]	0
Repayments of Long-term Debt																							445,072	156,172		57,223
Issuance of common stock																							717	1,285		247,188
Available-for-sale Securities, Equity Securities					$ 1,330									75,430									$ 1,330	75,430
Number of Guaranteed Structured Transactions For Radian Guaranty | transaction					2																		2
Convertible Debt [Member]
Supplemental Notes [Abstract]
Loss on induced conversion and debt extinguishment (Note 12)																							$ (17,200)
Senior Notes Due 2020 [Member]
Supplemental Notes [Abstract]
Debt Instrument, Face Amount		$ 350,000																$ 350,000
Debt Instrument, Interest Rate, Stated Percentage		5.25%			5.25%													5.25%					5.25%
Proceeds/payments related to issuance or exchange of debt, net		$ 343,300
Senior Notes Due 2017
Supplemental Notes [Abstract]
Debt Instrument, Interest Rate, Stated Percentage					9.00%																		9.00%
Loss on induced conversion and debt extinguishment (Note 12)							$ (15,000)
Debt Instrument, Repurchased Face Amount																											$ 195,500
Convertible Senior Notes Due 2017
Supplemental Notes [Abstract]
Redemption of long-term debt		389,100
Debt Instrument, Interest Rate, Stated Percentage					3.00%																		3.00%
Loss on induced conversion and debt extinguishment (Note 12)		$ (52,300)
Convertible Senior Notes Due 2017 | Convertible Debt [Member]
Supplemental Notes [Abstract]
Debt Instrument, Face Amount																														$ 450,000
Debt Instrument, Interest Rate, Stated Percentage																													3.00%
Proceeds/payments related to issuance or exchange of debt, net				$ 391,300
Debt Instrument, Interest Rate, Effective Percentage																													9.75%
Long-term Debt, Gross					$ 22,233									52,370									$ 22,233	52,370
Debt Instrument, Repurchased Face Amount					$ 30,100																		$ 30,100
Convertible Senior Notes Due 2019
Supplemental Notes [Abstract]
Debt Instrument, Interest Rate, Stated Percentage					2.25%																		2.25%
Convertible Senior Notes Due 2019 | Convertible Debt [Member]
Supplemental Notes [Abstract]
Debt Instrument, Face Amount																												$ 400,000
Debt Instrument, Interest Rate, Stated Percentage																												2.25%
Proceeds/payments related to issuance or exchange of debt, net																						$ 389,800
Debt Instrument, Interest Rate, Effective Percentage																												6.25%
Long-term Debt, Gross					$ 68,024									389,992									$ 68,024	389,992
Debt Instrument, Repurchased Face Amount					$ 322,000																		$ 322,000
Senior Notes Due 2019 [Member]
Supplemental Notes [Abstract]
Debt Instrument, Face Amount			$ 300,000
Debt Instrument, Interest Rate, Stated Percentage			5.50%		5.50%																		5.50%
Proceeds/payments related to issuance or exchange of debt, net			$ 293,800
Parent Company
Condensed Financial Statements, Captions [Line Items]
Restricted Cash Held As Collateral For Insurance Trust Agreement					$ 100									100									$ 100	100
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months					22,233																		22,233
Investments					390,754									230,826									390,754	230,826
Fixed-maturities available for sale—at fair value (amortized cost $2,856,468 and $1,893,356)					79,336									41,176									79,336	41,176
Short-term investments—at fair value					311,418									158,658									311,418	158,658
Notes Receivable, Related Parties														300,000										300,000
Supplemental Notes [Abstract]
Total Operating Expenses and Interest Expense Allocated to Subsidiaries From Parent Company																							108,538	89,038		92,532
Dividends Received From Consolidated Subsidiaries																							40,400	446,200
Investments in and Advances to Affiliates, at Fair Value, Period Increase (Decrease)																							2,500	398,300		139,100
Payments to Acquire Interest in Subsidiaries and Affiliates																							1,500	182,307		139,103
Proceeds from Contributions from Affiliates																							15,000	113,784		0
Tax Payments to Parent from Subsidiaries																							51,200	16,000		8,800
Loss on induced conversion and debt extinguishment (Note 12)																							(75,075)	(94,207)		0
Repayments of Long-term Debt																							445,072	156,172		57,223
Issuance of common stock																							717	1,285		247,188
Long-term Debt, Maturities, Repayments of Principal after Year Five					350,000																		350,000
Long-term Debt, Maturities, Repayments of Principal in Year Four					368,024																		368,024
Long-term Debt, Maturities, Repayments of Principal in Year Four					350,000																		350,000
Long-term Debt, Gross					1,090,257																		$ 1,090,257
Related Party Transaction, Rate																							0.00%
Available-for-sale Securities, Equity Securities					0									25,510									$ 0	25,510
Qualified Deposit With The U.S. Department Of Treasury Relating To Prior Examinations					89,000																		89,000
Parent Company | Convertible Senior Notes Due 2017
Supplemental Notes [Abstract]
Debt Instrument, Repurchased Face Amount					30,100																		30,100
Parent Company | Convertible Senior Notes Due 2019
Supplemental Notes [Abstract]
Long-term Debt, Gross					68,000																		68,000
Debt Instrument, Repurchased Face Amount					322,000																		322,000
Clayton Group Holdings Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Notes Receivable, Related Parties					300,000																		300,000
Increase (Decrease) Due from Other Related Parties																							31,200
Radian Guaranty [Member]
Condensed Financial Statements, Captions [Line Items]
Repayments of Related Party Debt	$ 201,600
Supplemental Notes [Abstract]
Payments for Capital Contributions to Wholly-Owned Subsidiaries																								100,000
Transfer from Investments																								116,500
Transfer to Investments	123,400
Increase (Decrease) in Notes Payable, Related Parties	$ 325,000
Surplus Notes					0									325,000									0	325,000
Payments to Acquire Notes Receivable																								208,500
Statutory Accounting Practices, Statutory Policyholders' Surplus, Balance					1,349,700									1,686,500									1,349,700	1,686,500		1,325,200
Radian Reinsurance [Member]
Supplemental Notes [Abstract]
Investments in and Advances to Affiliates, at Fair Value, Period Increase (Decrease)																								266,000
Payments for Capital Contributions to Wholly-Owned Subsidiaries																								50,000
Transfer from Investments																								216,000
Statutory Accounting Practices, Statutory Capital and Surplus Required					20,000																		20,000
Statutory Accounting Practices, Statutory Policyholders' Surplus, Balance					147,600									$ 138,700									147,600	138,700
Radian Mortgage Guaranty Inc. [Member]
Supplemental Notes [Abstract]
Payments for Capital Contributions to Wholly-Owned Subsidiaries																								20,000
RDN Investments [Member]
Supplemental Notes [Abstract]
Dividends Received From Consolidated Subsidiaries																								215,200
Payments for Capital Contributions to Wholly-Owned Subsidiaries																							1,500
Transfer to Investments																							25,400	116,500
Proceeds from Contributions from Affiliates																								98,700
Radian MI Services Inc. [Member]
Supplemental Notes [Abstract]
Dividends Received From Consolidated Subsidiaries																							5,000
Payments for Capital Contributions to Wholly-Owned Subsidiaries																										20,000
Proceeds from Contributions from Affiliates																								15,000
Radian Clayton Holdings Inc. [Member]
Supplemental Notes [Abstract]
Payments for Capital Contributions to Wholly-Owned Subsidiaries																								12,100		19,000
Transfer from Investments																							1,000
Radian Insurance [Member]
Supplemental Notes [Abstract]
Payments to Acquire Interest in Subsidiaries and Affiliates																							19,000
Radian Mortgage Reinsurance [Member]
Supplemental Notes [Abstract]
Payments for Capital Contributions to Wholly-Owned Subsidiaries																								200		100
Enhance Financial Services Group, Inc. [Member]
Supplemental Notes [Abstract]
Transfer from Investments																								$ 216,000
Proceeds from Contributions from Affiliates																							15,000
Radian Mortgage Assurance [Member]
Supplemental Notes [Abstract]
Payments to Acquire Interest in Subsidiaries and Affiliates																							8,600
Statutory Accounting Practices, Statutory Capital and Surplus Required					5,000																		5,000
Statutory Accounting Practices, Statutory Policyholders' Surplus, Balance					8,600																		8,600
Risk In Force					$ 0																		0
Radian Mortgage Insurance Inc [Member]
Supplemental Notes [Abstract]
Payments to Acquire Interest in Subsidiaries and Affiliates																							$ 2,800
Radian Guaranty Inc [Member]
Supplemental Notes [Abstract]
Payments for Capital Contributions to Wholly-Owned Subsidiaries																										$ 100,000

[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.