Stockholders' Equity - Additional Information (Detail) - USD ($)					1 Months Ended				12 Months Ended
	Feb. 12, 2016	Jan. 27, 2016	Aug. 15, 2012	Aug. 13, 2009	Feb. 28, 2014	Jul. 31, 2013	Feb. 28, 2013	Oct. 31, 2011	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 18, 2013	May. 23, 2011
Class Of Stock [Line Items]
Weighted average contractual term of awards outstanding									1 year 8 months 27 days	1 year 5 months 5 days	1 year 4 months 28 days
Options vested									0	0	0
Options granted									0	0	0
Cash received from option exercise under all share-based payment arrangements									$ 300,000	$ 10,100,000	$ 400,000
Tax benefit from share based payment arrangement									100,000	10,700,000	1,200,000
Aggregate intrinsic value of options exercised									0	40,100,000	4,800,000
Aggregate intrinsic value of options outstanding									0	3,000,000	44,000,000
Aggregate intrinsic value of options exercisable									$ 0	$ 3,000,000	$ 44,000,000
Subsequent Event
Class Of Stock [Line Items]
Number of preferred stock distributed to common stockholders	1	1
Preferred stock purchase rights exercise price		$ 30
Preferred stock purchase discount percentage		50.00%
Minimum | Subsequent Event
Class Of Stock [Line Items]
Equity ownership percentage		20.00%
Warrant
Class Of Stock [Line Items]
Weighted average contractual term of awards outstanding and exercisable									2 years 9 months 4 days	3 years 9 months 4 days	3 years 7 months 28 days
Exercised									0	170,000	0
Convertible Notes | 1.50% Senior Subordinated Notes Due March 15, 2018
Class Of Stock [Line Items]
Debt instrument, interest rate, stated percentage									1.50%	1.50%		1.50%
Convertible Notes | 2.50% Senior Subordinated Notes Due June 2016
Class Of Stock [Line Items]
Debt instrument, interest rate, stated percentage									2.50%	2.50%			2.50%
Stock Options
Class Of Stock [Line Items]
Compensation expense related to stock grants									$ 0	$ 0	$ 0
Restricted Stock
Class Of Stock [Line Items]
Common stock reserved for issuance									11,400,000	18,500,000	20,000,000
Share based compensation awards granted in period									355,588	256,480	1,247,879
Share based compensation awards granted in period, fair market value									$ 7,200,000	$ 10,400,000	$ 31,600,000
Common shares available for issuance									2,600,000
Restricted common stock, value of shares withheld									$ 15,500,000	$ 16,000,000	$ 3,700,000
Restricted Stock | Maximum
Class Of Stock [Line Items]
Share based compensation awards vesting period									5 years	5 years	5 years
Stock Incentive Plan 2009
Class Of Stock [Line Items]
Number of common stock shares authorized under Equity Incentive Plan				3,000,000
Plan expiration date				Aug. 13, 2019
Amended and Restated Stock Incentive Plan 2009
Class Of Stock [Line Items]
Number of common stock shares authorized under Equity Incentive Plan			7,000,000
Plan expiration date			Aug. 15, 2022
Number of additional common stock shares approved for issuance under amended and restated 2009 Equity Incentive Plan			4,000,000
Common stock reserved for issuance									2,845,017
Previous Plan
Class Of Stock [Line Items]
Common stock reserved for issuance									0
February 2013 Program
Class Of Stock [Line Items]
Repurchase of common stock authorized value							$ 300,000,000
Period of common stock repurchase, years							3 years
2011 Program
Class Of Stock [Line Items]
Repurchase of common stock authorized value								$ 200,000,000
Period of common stock repurchase, years								3 years
July 2013 Program
Class Of Stock [Line Items]
Repurchase of common stock authorized value						$ 300,000,000
Period of common stock repurchase, years						3 years
Accounts payable and accrued expenses									$ 13,300,000
February 2014 Program
Class Of Stock [Line Items]
Repurchase of common stock authorized value					$ 500,000,000
Period of common stock repurchase, years					3 years
Accounts payable and accrued expenses									$ 500,000,000