Schedule II Financial Information of Registrant Parent Company Only Financial Information (Details) (USD $)			0 Months Ended	12 Months Ended			12 Months Ended									2 Months Ended	6 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended							1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended					1 Months Ended		0 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jan. 04, 2013 9.00% Senior Notes due 2017 [Member]	Dec. 14, 2012 9.00% Senior Notes due 2017 [Member]	Dec. 31, 2012 9.00% Senior Notes due 2017 [Member]	Dec. 03, 2012 9.00% Senior Notes due 2017 [Member]	Dec. 15, 2012 Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 31, 2012 Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 03, 2012 Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 31, 2011 Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Jun. 01, 2005 Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 31, 2010 Seven Point Seven Five Percent Debentures due 2011 [Member]	Dec. 31, 2012 3.00% Convertible Senior Notes due 2017 [Member]	Dec. 31, 2011 3.00% Convertible Senior Notes due 2017 [Member]	Nov. 15, 2010 3.00% Convertible Senior Notes due 2017 [Member]	Feb. 23, 2012 Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Sep. 30, 2012 Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Dec. 31, 2012 Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Dec. 31, 2011 Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Feb. 01, 2003 Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Dec. 31, 2011 Parent Company	Dec. 31, 2012 Parent Company		Dec. 31, 2011 Parent Company		Dec. 31, 2010 Parent Company		Dec. 31, 2010 Parent Company Seven Point Seven Five Percent Debentures due 2011 [Member]	Feb. 29, 2012 Subsidiaries [Member]	Dec. 31, 2011 Subsidiaries [Member]	Feb. 29, 2012 Radian Guaranty Inc [Member]	Dec. 31, 2011 Radian Guaranty Inc [Member]	Dec. 31, 2011 Radian Guaranty Inc [Member]	Dec. 31, 2010 Radian Guaranty Inc [Member]	Dec. 31, 2011 Enhance Financial Services [Member]	Dec. 31, 2012 Radian Mortgage Reinsurance [Member]	Dec. 31, 2010 CMAC Of Texas [Member]	Feb. 15, 2013 Repayment of Debt [Member] Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Feb. 15, 2013 Repayment of Debt [Member] Parent Company Five Point Six Two Five Percent Senior Notes due 2013 [Member]	Jan. 04, 2013 Debt Due 2015 Exchange [Member] 9.00% Senior Notes due 2017 [Member]	Jan. 04, 2013 Debt Due 2015 Exchange [Member] Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 31, 2012 Debt Due 2015 Exchange [Member] Five Point Three Seven Five Percent Senior Notes due 2015 [Member]	Dec. 31, 2012 Requirement Per Fannie Mae Approval [Member] Radian Guaranty Inc [Member]
Supplemental Notes [Abstract]
Income Taxes, Parent Refund To Subsidiary																								$ 95,400,000
Restricted Funds Included In Short Term Investments																					27,700,000	55,600,000		27,700,000
Restricted Cash Held As Collateral For Insurance Trust Agreement																					1,100,000	400,000		1,100,000
Total Operating Expenses and Interest Expense Allocated to Subsidiaries From Parent Company																						93,200,000		100,700,000		105,200,000
Proceeds from Contributions from Affiliates																						0		0		268,530,000
Capital Contributions																						100,384,000	[1]	50,587,000	[1]	423,146,000	[1]		100,400,000		100,000,000		30,000,000	322,000,000	20,100,000	100,000	101,000,000						300,000
Tax Payments to Parent from Subsidiaries																						36,800,000
Income Taxes, Parent Refund To Subsidiary, Net of Intercompany Receipts																														67,000,000
Consolidation, Wholly Owned Subsidiary, Parent Ownership Interest Changes, Transfer of Interest by Parent																																16,600,000
Payments for (Proceeds from) Businesses and Interest in Affiliates																					5,700,000
Redemption of long-term debt																146,500,000	24,100,000	170,600,000										31,900,000										79,449,000	79,400,000		195,176,000
Debt Instrument, Offering Date					Dec. 03, 2012
Debt Instrument, Face Amount											250,000,000		450,000,000	450,000,000	450,000,000					250,000,000
Debt Instrument, Interest Rate, Stated Percentage						9.00%					5.375%	7.75%			3.00%			5.625%		5.625%
Price Per Principal Amount Tendered for Repurchase of Long Term Debt Through Modified Dutch Auction Tender Offer																900
Principal Amount of Note Used as Basis for Determining Tender Cap Range of Purchase																1,000
Percent of Principal Amount of Notes Purchased in Modified Dutch Auction Tender Offer for Long Term Debt																59.00%
Gains (Losses) on Extinguishment of Debt																15,200,000	1,000,000					(16,175,000)		0		(2,496,000)
Debt Instrument, Exchange, Early Participation Cutoff Date				Dec. 14, 2012
Debt Instrument, Maturity Date					Jun. 15, 2017			Jun. 15, 2015
Debt Instrument, Exchange Offer, Last Payment Date							Dec. 15, 2012
Debt Instrument, Issuance Date					Dec. 31, 2012
Debt Conversion, Converted Instrument, Expiration or Due Date			Jan. 04, 2013																																					Jan. 04, 2013
Principal Amount of Notes Used in Calculation of Debt Exchange									1,000
Debt Issuance Cost Per Principal Amount of Notes									25.00
Interest Payable, Current																																										600,000
Payments of Debt Issuance Costs																																								4,900,000	4,900,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months																						79,449,000
Long-term Debt, Maturities, Repayments of Principal in Year Two																						0
Long-term Debt, Maturities, Repayments of Principal in Year Three																						249,868,000
Long-term Debt, Maturities, Repayments of Principal in Year Four																						0
Long-term Debt, Maturities, Repayments of Principal in Year Five																						334,254,000
Long-term Debt, Maturities, Repayments of Principal after Year Five																						0
Long-term debt	663,571,000	818,584,000						249,868,000		249,819,000			334,254,000	316,498,000					252,267,000		818,584,000	663,571,000		818,584,000
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 98,909,000	$ 96,403,000																			$ 46,998,000	$ 48,786,000		$ 46,998,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001																			$ 0.001	$ 0.001		$ 0.001
Common Stock, Shares Authorized	325,000,000	325,000,000																			325,000,000	325,000,000		325,000,000
Common Stock, Shares, Issued	151,131,173	150,666,446																			150,666,446	151,131,173		150,666,446
Common Stock, Shares, Outstanding	133,647,216	133,199,159																			133,199,159	133,647,216		133,199,159
Treasury Stock, Shares	17,483,957	17,467,287																			17,467,287	17,483,957		17,467,287

[1] See Note A.