Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest at Dec. 31, 2011	$ 3,795,436,000	$ 131,757,000	$ 2,488,941,000	$ 1,651,829,000	$ (484,123,000)	$ 7,032,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends, Common Stock, Cash	(45,214,000)	0	0	(45,214,000)	0	0
Stocks Acquired Issued For Benefit Plans	39,000	0	0	0	39,000	0
Stock Issued During Period Value Stock Options Exercised Net Of Amortization Forfeitures	51,156,000	1,295,000	50,093,000	0	(232,000)	0
Treasury Stock, Value, Acquired, Cost Method	(339,117,000)	0	0	0	(339,117,000)	0
Translation adjustment recorde as loss on sales of CRO	(9,722,000)					(9,722,000)
Stockholders' Equity, Other	(48,126,000)	0	(48,126,000)	0	0	0
Forward Contract Indexed to Issuer's Equity, Redeemable Stock, Redemption Requirements, Amount	(50,000,000)	0	(50,000,000)	0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	11,062,000	451,000	33,608,000	(414,000)	(22,583,000)	0
Stock Issued During Period, Value, Conversion of Convertible Securities		0
APIC impact of debt exchanged/converted	(54,546,000)		(54,546,000)	0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	194,874,000	0	0	194,874,000	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(130,000)	0	0	0	0	(130,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest CLONE at Dec. 31, 2012	3,505,712,000	133,503,000	2,419,970,000	1,801,075,000	(846,016,000)	(2,820,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends, Common Stock, Cash	(62,928,000)	0	0	(62,928,000)	0	0
Stocks Acquired Issued For Benefit Plans	57,000	0	0	0	57,000	0
Stock Issued During Period Value Stock Options Exercised Net Of Amortization Forfeitures	22,765,000	744,000	22,088,000	0	(67,000)	0
Treasury Stock, Value, Acquired, Cost Method	(220,971,000)	0	0	0	(220,971,000)	0
Translation adjustment recorde as loss on sales of CRO		0	0	0	0
Forward Contract Indexed to Issuer's Equity, Redeemable Stock, Redemption Requirements, Amount	0	0	50,000,000	0	(50,000,000)	0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	14,032,000	376,000	29,849,000	(916,000)	(15,277,000)	0
Stock Issued During Period, Value, Conversion of Convertible Securities		(1,000)
APIC impact of debt exchanged/converted	143,610,000		143,611,000	0	0	0
Temporary Equity, Carrying Amount, Period Increase (Decrease)	(331,101,000)	0	(331,101,000)	0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(43,432,000)	0	0	(43,432,000)	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	279,000	0	0	0	0	279,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest CLONE at Dec. 31, 2013	2,740,803,000	134,624,000	2,047,195,000	1,693,799,000	(1,132,274,000)	(2,541,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends, Common Stock, Cash	(80,297,000)	0	0	(80,297,000)	0	0
Stock Issued During Period Value Stock Options Exercised Net Of Amortization Forfeitures	14,473,000	312,000	13,883,000	0	278,000	0
Treasury Stock, Value, Acquired, Cost Method	(220,438,000)	0	0	0	(220,438,000)	0
Adjustments to Additional Paid in Capital; Equity Component of Capped Call Transaction	0	0	139,794,000	0	(139,794,000)	0
Forward Contract Indexed to Issuer's Equity, Redeemable Stock, Redemption Requirements, Amount	(15,000,000)	0	(15,000,000)	0	0	0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	13,524,000	269,000	36,462,000	(643,000)	(22,564,000)	0
Stock Issued During Period, Value, Conversion of Convertible Securities		(3,221,000)
APIC impact of debt exchanged/converted	187,983,000		191,204,000	0	0	0
Temporary Equity, Carrying Amount, Period Increase (Decrease)	179,396,000	0	179,396,000	0	0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	144,527,000	0	0	144,527,000	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(284,000)	0	0	0	0	(284,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest CLONE at Dec. 31, 2014	$ 2,588,721,000	$ 138,426,000	$ 2,210,526,000	$ 1,757,386,000	$ (1,514,792,000)	$ (2,825,000)