DEBT (Narrative) (Details) - USD ($)		1 Months Ended	12 Months Ended
	Dec. 15, 2016	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2017	Mar. 30, 2017	Jul. 31, 2015	Jun. 15, 2011
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 2,200,000,000.0	$ 1,500,000,000.0
Amortization of debt issuance costs			$ 2,722,000	$ 2,529,000	$ 2,264,000
Amount drawn from loan			1,307,000,000	680,000,000	545,000,000
Principal amount paid			0	184,313,000	$ 2,519,000
Common stock from the exercise of call option with hedge participants (in shares)	2,900,000
Common stock from the exercise of call option with hedge participants, value			$ 121,600,000	$ 123,100,000
Price per share (in dollars per share)			$ 41.77	$ 41.78
Convertible Debt
Debt Instrument [Line Items]
Strike price of the call transaction (in dollars per share)								$ 26.42	$ 28.72
Strike price of warrant transactions (in dollars per share)								$ 32.22	$ 35.03
Warrants exercised (in shares)			8,707,202
Common stock from the exercise of warrants (in shares)			2,839,743
Warrants outstanding (in shares)			0
Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity						1,000,000,000
Line of credit facility outstanding			$ 655,000,000	$ 165,000,000
Weighted average interest rate on debt			3.70%	2.20%
Revolving Credit Facility | Level 2
Debt Instrument [Line Items]
Outstanding borrowings			$ 661,000,000
Standby Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity						60,000,000
Swingline Loan
Debt Instrument [Line Items]
Maximum borrowing capacity						60,000,000
Term Loan A Facility | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity						500,000,000.0
Line of credit facility outstanding			$ 500,000,000	$ 500,000,000
Weighted average interest rate on debt			3.60%	2.20%
Term Loan A Facility | Secured Debt | Level 2
Debt Instrument [Line Items]
Outstanding borrowings			$ 502,700,000
Term loan A-1 | Secured Debt
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 700,000,000
Capitalized incremental financing costs		$ 19,100,000
Amount drawn from loan		$ 700,000,000
Line of credit facility outstanding			700,000,000
Term loan A-1 | Secured Debt | Level 2
Debt Instrument [Line Items]
Outstanding borrowings			703,700,000
Senior Credit Facility
Debt Instrument [Line Items]
Cash balance threshold above which excess amount is not subject to any restriction of use or investment			40,000,000
Capitalized incremental financing costs			$ 19,100,000	$ 4,500,000
Senior Credit Facility | Minimum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage			0.15%
Senior Credit Facility | Maximum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage			0.35%
Senior Credit Facility | Eurodollar | Minimum
Debt Instrument [Line Items]
Interest rates available to the company at its option			1.00%
Senior Credit Facility | Eurodollar | Maximum
Debt Instrument [Line Items]
Interest rates available to the company at its option			2.00%
Senior Credit Facility | Federal Funds
Debt Instrument [Line Items]
Interest rates available to the company at its option			0.50%
Senior Credit Facility | One Month Eurodollar Rate
Debt Instrument [Line Items]
Interest rates available to the company at its option			1.00%
Senior Credit Facility | Standby Letters of Credit
Debt Instrument [Line Items]
Line of credit facility outstanding			$ 0
Letters of credit outstanding			600,000	500,000
July 2014 Amendment
Debt Instrument [Line Items]
Amortization of debt issuance costs			$ 0	$ 500,000
2016 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding									$ 230,000,000
Interest rate on debt				1.625%	1.625%
2016 Convertible Senior Notes | Convertible Debt
Debt Instrument [Line Items]
Principal amount paid	$ 227,100,000
Stock issued during period, shares, conversion of convertible securities (in shares)	2,900,000
Settlement of convertible notes	$ 122,000,000
Gain or loss on extinguishment	$ 0
Interest rate on debt	1.625%