FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 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		$ 7,600
Derivatives Not Designated as Hedging Instruments
Foreign currency gains (losses), net of derivative activity	(5,100)	$ (2,600)	(11,000)	$ (7,000)
Foreign Currency Contracts, Translation Risk
Derivatives Not Designated as Hedging Instruments
Foreign currency gains (losses) recorded in Foreign currency transactions and other	900	3,900	(200)	300
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	0		0		0
Foreign Currency Contracts, Transaction Risk
Derivatives Not Designated as Hedging Instruments
Foreign currency gains (losses) recorded in Foreign currency transactions and other	20,800	$ 3,600	27,600	16,000
Foreign currency derivative instruments not designated as hedging instruments at fair value, net	300		300		(300)
Foreign currency derivative assets recorded in Prepaid expenses and other current assets	500		500		700
Foreign currency derivative liabilities recorded in Accrued expenses and other current liabilities	200		200		1,000
Foreign Currency Contracts
Derivatives Not Designated as Hedging Instruments
Net cash inflow from settlement of derivative contracts included in operating activities			23,100	$ 23,600
Long-term Investments
Derivatives Not Designated as Hedging Instruments
Available-for-sale securities, amortized cost basis	9,527,130		9,527,130		9,407,136
Ctrip.com International, Ltd.
Derivatives Not Designated as Hedging Instruments
Embedded derivative, gain on embedded derivative	600		2,000
Ctrip.com International, Ltd. | Ctrip convertible debt securities | Long-term Investments
Derivatives Not Designated as Hedging Instruments
Available-for-sale securities, amortized cost basis	1,275,000		1,275,000		1,275,000	$ 25,000	$ 500,000	$ 250,000	$ 500,000
Embedded derivative, fair value of embedded derivative	$ 3,800		$ 3,800		$ 1,800