DEBT (Details 3) (USD $)	3 Months Ended	6 Months Ended			3 Months Ended		6 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Jun. 30, 2011 Convertible Notes	Jun. 30, 2010 Convertible Notes	Jun. 30, 2011 Convertible Notes	Jun. 30, 2010 Convertible Notes	Mar. 31, 2010 1.25% Convertible Senior Notes due March 2015 Days	Mar. 31, 2010 1.25% Convertible Senior Notes due March 2015	Jun. 30, 2011 1.25% Convertible Senior Notes due March 2015	Jun. 30, 2011 0.75% Convertible Senior Notes due September 2013	Dec. 31, 2006 0.75% Convertible Senior Notes due September 2013	Sep. 30, 2006 0.75% Convertible Senior Notes due September 2013
DEBT
Estimated market value of outstanding senior notes		$ 1,000,000,000		$ 900,000,000
Debt Instrument Conversion Terms
Reclassification adjustment for convertible debt in mezzanine		(88,184,000)									(88,184,000)
Cash repayment of principal amount of convertible debt		200,000	145,800,000
Shares issued in satisfaction of the conversion value in excess of the principle amount for convertible debt (in shares)		4,869	2,797,589
Cash payment in satisfaction of conversion value in excess of principal amount			27,600,000
Aggregate principal amount									575,000,000	575,000,000			172,500,000	172,500,000
Interest rate on Convertible Senior Notes (as a percent)									1.25%	1.25%		0.75%	0.75%
Debt financing costs paid										12,900,000
Conversion price (in dollars per share)									$ 303.06	$ 303.06		$ 40.38	$ 40.38
Minimum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days)									20
Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days)									30
Ratio of closing share price to conversion price as a condition for conversion of convertible 2015 Senior Notes, minimum (as a percent)									150.00%
Additional payments in the form of additional shares of common stock to the holders of the 2015 Notes, low end of range									0
Additional payments in the form of additional shares of common stock to the holders of the 2015 Notes, high end of range									132,700,000
Effective interest rate at debt origination or modification (as a percent)									5.89%	5.89%			8.00%
Interest expense related to convertible notes					7,600,000	8,600,000	15,100,000	12,600,000
Contractual coupon interest related to convertible notes included in interest expense					1,800,000	1,900,000	3,600,000	2,400,000
Amortization of debt discount included in interest expense		10,553,000	9,466,000		5,300,000	6,200,000	10,500,000	9,500,000
Amortization of debt issuance costs included in interest expense					500,000	500,000	1,000,000	700,000
Unamortized debt issuance costs written off to interest expense related to early conversion of convertible debt	400,000		1,000,000			400,000		1,000,000
Effective interest rate during the period (as a percent)					6.30%	6.80%	6.30%	7.10%
Variable rate used to estimate the fair value of debt at conversion date							LIBOR
Gain (loss) on extinguishment of debt, pretax		(32,000)	(8,108,000)			(2,900,000)		(8,100,000)
Gain (loss) on extinguishment of debt, net of tax						$ (1,700,000)		$ (4,900,000)
Convertible Debt - Conversion Spread Hedges
Number of shares the Company is entitled to purchase from Goldman Sachs and Merrill Lynch under hedge agreement (in shares)													4,300,000
Number of shares Goldman Sachs and Merrill Lynch are entitled to purchase from the Company under the hedge agreement (in shares)													4,300,000
Strike price of shares purchasable by counterparties under hedge agreement (in dollars per share)												$ 50.47	$ 50.47