DEBT (Details) (USD $)	1 Months Ended	9 Months Ended			1 Months Ended						1 Months Ended			1 Months Ended		9 Months Ended		1 Months Ended
	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2013 2018 Convertible Senior Notes and 2020 Convertible Senior Notes note_series	Sep. 30, 2013 2018 Convertible Senior Notes and 2020 Convertible Senior Notes Minimum D	Sep. 30, 2013 2018 Convertible Senior Notes and 2020 Convertible Senior Notes Maximum	Sep. 30, 2014 2020 Convertible Senior Notes	Dec. 31, 2013 2020 Convertible Senior Notes	Sep. 30, 2013 2020 Convertible Senior Notes	Sep. 30, 2013 2018 Convertible Senior Notes note_series	Sep. 30, 2014 2018 Convertible Senior Notes	Dec. 31, 2013 2018 Convertible Senior Notes	Sep. 30, 2013 2017 Convertible Senior Notes	Oct. 31, 2010 2017 Convertible Senior Notes	Sep. 30, 2014 2017 Convertible Senior Notes	Dec. 31, 2013 2017 Convertible Senior Notes	Oct. 31, 2010 2017 Convertible Senior Notes Minimum D	Oct. 31, 2010 2017 Convertible Senior Notes Maximum
Debt
Principal amount outstanding		$ 1,028,809,000		$ 1,028,822,000				$ 450,000,000	$ 450,000,000			$ 350,000,000	$ 350,000,000			$ 228,809,000	$ 228,822,000
Unamortized discount		(185,316,000)		(210,992,000)				(100,763,000)	(111,015,000)			(56,312,000)	(65,733,000)			(28,241,000)	(34,244,000)
Net carrying amount		843,493,000		817,830,000				349,237,000	338,985,000			293,688,000	284,267,000			200,568,000	194,578,000
Aggregate principal amount of notes issued					800,000,000					450,000,000	350,000,000				450,000,000
Number of note series					2						1
Net proceeds after debt issuance cost					775,600,000										436,000,000
Conversion rate of common stock					12.1318										34.2759
Conversion ratio, principal amount					1,000										1,000
Initial conversion price of shares (in dollars per share)					$ 82.43										$ 29.18
Number of days within 30 consecutive trading days in which the closing price of the entity's common stock must exceed the conversion price for the notes to be redeemable						20												20
Number of consecutive trading days during which the closing price of the entity's common stock must exceed the conversion price for at least 20 days in order for the notes to be redeemable					30 days										30 days
Convertibility of debt, closing price of stock test, percentage of stock price to conversion price that must be exceeded					130.00%										130.00%
Number of consecutive business days immediately after any five consecutive trading day period during the note measurement period					5 days										5 days
Number of consecutive trading days before five consecutive business days during the note measurement period					5 days										5 days
Convertibility of debt, trading price of debt test, percentage of closing price of stock used in calculation							98.00%												98.00%
Notes stated interest rate percentage								1.875%				1.125%				2.50%
If-converted value in excess of the principal amount of debt																291,500,000
Principal amount of the 2017 Notes converted														221,200,000
Convertible Bond Hedge
Common stock covered under convertible bond hedge (in shares)	9,705,442		9,705,442
Exercise price (in dollars per unit)	82.43
Purchase of convertible bond hedge	179,400,000	0	179,390,000
Warrant Transactions
Number of common stock called by warrants (in shares)	9,705,442		9,705,442
Exercise price (in dollars per share)	96.43		96.43
Number of trading days over which warrants are exercisable	80 days
Proceeds from issuance of warrants	$ 121,700,000	$ 0	$ 121,675,000