FINANCIAL INSTRUMENTS (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended											9 Months Ended
	Sep. 30, 2014	Apr. 30, 2014	Sep. 30, 2014 Level 1		Sep. 30, 2014 Level 2		Sep. 30, 2014 Level 3		Sep. 30, 2014 Carrying Value		Dec. 31, 2013 Notes	Sep. 30, 2014 Maximum
Fair Value Measurements
Convertible senior notes			$ 0	[1]	$ 468,972,000	[1]	$ 0	[1]	$ 102,065,000	[1]
Closing sale price (in dollars per share)	$ 96.92	$ 64.00
Initial conversion price of notes into common stock (in dollars per share)											$ 24.82
Debt Instrument, Convertible, Conversion Premium, Shares	3.6											4.8
Estimated conversion value	$ 349,000,000.000

[1] The fair value of the Notes was based on the Company’s closing stock price of $96.92 per share at September 30, 2014 compared to a conversion price of $24.82 per share which, if converted, would result in an approximate conversion premium of 3.6 million shares or $349 million of cash. The maximum conversion premium that can be due on the Notes is 4.8 million shares, which assumes no increases in the conversion rate for certain corporate events.