Schedule II Financial Information of Registrant Parent Company Balance Sheet (Details) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Assets
Trading securities—at fair value	$ 1,633,584		$ 2,238,741
Other short-term investments	1,300,872		935,852
Cash	30,465		22,880		29,408	33,020
Restricted cash	14,031		22,527
Investment in subsidiaries, at equity in net assets	2,200,000
Property and equipment, at cost (less accumulated depreciation of $50,648 and $49,632)	27,248	[1]	10,496	[1]
Other assets	375,491		379,903
Assets held for sale	1,736,444	[2]	1,768,061		2,000,000
Total assets	6,859,963		5,621,691
LIABILITIES AND STOCKHOLDERS’ EQUITY
Long-term debt	1,209,926		930,072
Other liabilities	326,743		377,930
Liabilities held for sale	947,008		642,619
Total liabilities	4,688,213		4,682,046
Equity component of currently redeemable convertible senior notes (Note 11)	74,690		0
Common stock: par value $.001 per share; 485,000,000 shares authorized at December 31, 2014 and 2013; 208,601,020 and 190,636,972 shares issued at December 31, 2014 and 2013, respectively; 191,053,530 and 173,099,515 shares outstanding at December 31, 2014 and 2013, respectively	209		191
Treasury stock, at cost: 17,547,490 and 17,537,457 shares at December 31, 2014 and 2013, respectively	(892,961)		(892,807)
Additional paid-in capital	2,531,513		2,347,104
Retained earnings (deficit)	406,814		(552,226)
Accumulated other comprehensive income (“AOCI”)	51,485		37,383
Total common stockholders’ equity	2,097,060		939,645
Balance Sheet Parentheticals [Abstract]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	100,207		96,058
Common Stock, Par or Stated Value Per Share	$ 0.001		$ 0.001
Common Stock, Shares Authorized	485,000,000		485,000,000
Common Stock, Shares, Issued	208,601,020		190,636,972
Common Stock, Shares, Outstanding	191,053,530		173,099,515
Treasury Stock, Shares	17,547,490		17,537,457
Parent Company
Assets
Trading securities—at fair value	5,447		5,240
Other short-term investments	631,934		633,178
Cash	1,951		4,304		2,978	453
Restricted cash	124		123
Investment in subsidiaries, at equity in net assets	2,746,915		1,419,360
Debt issuance costs	17,627		15,741
Due from affiliates, net	13,110		12,283
Accounts and Notes Receivable, Net	305,856		8,105
Property and equipment, at cost (less accumulated depreciation of $50,648 and $49,632)	1,624		1,281
Other assets	16,660		12,880
Assets held for sale	18,027		0
Total assets	3,759,275		2,112,495
LIABILITIES AND STOCKHOLDERS’ EQUITY
Accrued interest payable	6,796		5,551
Accrued compensation expense	86,258		132,848
Long-term debt	1,209,926		930,072
Federal income taxes—current and deferred	262,583		98,476
Other liabilities	3,935		5,903
Liabilities held for sale	18,027		0
Total liabilities	1,587,525		1,172,850
Equity component of currently redeemable convertible senior notes (Note 11)	74,690		0
Common stock: par value $.001 per share; 485,000,000 shares authorized at December 31, 2014 and 2013; 208,601,020 and 190,636,972 shares issued at December 31, 2014 and 2013, respectively; 191,053,530 and 173,099,515 shares outstanding at December 31, 2014 and 2013, respectively	209		191
Treasury stock, at cost: 17,547,490 and 17,537,457 shares at December 31, 2014 and 2013, respectively	(892,961)		(892,807)
Additional paid-in capital	2,531,513		2,347,104
Retained earnings (deficit)	406,814		(552,226)
Accumulated other comprehensive income (“AOCI”)	51,485		37,383
Total common stockholders’ equity	2,097,060		939,645
Total liabilities and stockholders’ equity	3,759,275		2,112,495
Balance Sheet Parentheticals [Abstract]
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 50,648		$ 49,632
Common Stock, Par or Stated Value Per Share	$ 0.001		$ 0.001
Common Stock, Shares Authorized	485,000,000		485,000,000
Common Stock, Shares, Issued	208,601,020		190,636,972
Common Stock, Shares, Outstanding	191,053,530		173,099,515
Treasury Stock, Shares	17,547,490		17,537,457

[1] Property and equipment, at cost less accumulated depreciation of $100,207 and $96,058 at December 31, 2014 and 2013, respectively.

[2] Assets held for sale are not part of the mortgage insurance or MRES segments.