FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Sep. 12, 2016	Dec. 11, 2015	May 26, 2015	Aug. 07, 2014
Fair Value Disclosures [Abstract]
Cost Method Investments	$ 7,600		$ 7,600
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses), net of derivative activity	(5,900)	$ (4,400)
Embedded Derivative, Gain on Embedded Derivative	1,400
Foreign Exchange Contracts, Translation Risk [Member]
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses) recorded in Foreign currency transactions and other	(1,100)	(3,600)
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	0		0
Foreign Exchange Contracts, Transaction Risk [Member]
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses) recorded in Foreign currency transactions and other	6,800	12,400
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	(100)		(300)
Foreign exchange derivative assets recorded in Prepaid expenses and other current assets	500		700
Foreign exchange derivative liabilities recorded in Accrued expenses and other current liabilities	600		1,000
Foreign Currency Contracts [Member]
Derivatives Not Designated as Hedging Instruments
Net cash inflow from settlement of derivative contracts included in operating activities	2,700	$ 22,300
Long-term Investments [Member]
Derivatives Not Designated as Hedging Instruments
Available-for-sale Securities, Amortized Cost Basis	9,602,027		9,407,136
Ctrip.com International, Ltd. [Member] | Ctrip convertible debt securities | Long-term Investments [Member]
Derivatives Not Designated as Hedging Instruments
Available-for-sale Securities, Amortized Cost Basis	1,275,000		1,275,000	$ 25,000	$ 500,000	$ 250,000	$ 500,000
Embedded Derivative, Fair Value of Embedded Derivative Asset	$ 3,200		$ 1,800