FAIR VALUE MEASUREMENTS (Derivatives) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 12, 2016	Dec. 11, 2015	May 26, 2015	Aug. 07, 2014
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses), net of derivative activity	$ (13,900,000)	$ (13,800,000)	$ (11,800,000)
Derivatives Designated as Hedging Instruments
Net Investment Hedges, Fair Value, Net	0	0
Proceeds from foreign currency contracts	0	453,818,000	14,354,000
Payments for foreign currency contracts	0	448,640,000	94,661,000
Embedded Derivative
Fair Value of Embedded Derivative Asset	1,800,000
Loss on Embedded Derivative	1,100,000
Foreign Exchange Contracts, Translation Risk
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses) recorded in "Foreign currency transactions and other"	3,400,000	(6,600,000)	13,700,000
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	0	0
Foreign Exchange Contracts, Transaction Risk
Derivatives Not Designated as Hedging Instruments
Foreign exchange gains (losses) recorded in "Foreign currency transactions and other"	(15,800,000)	(15,300,000)	(21,800,000)
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net	(300,000)	(300,000)
Foreign exchange derivative assets recorded in "Prepaid expenses and other current assets"	700,000	400,000
Foreign exchange derivative liabilities recorded in "Accrued expenses and other current liabilities"	1,000,000	700,000
Currency exchange derivatives
Derivatives Not Designated as Hedging Instruments
Proceeds for Derivative Instruments in Operating Activities	4,500,000
Payments for Derivative Instruments in Operating Activities		33,900,000	8,900,000
Derivatives Designated as Hedging Instruments
Proceeds from foreign currency contracts		5,200,000
Payments for foreign currency contracts			$ 80,300,000
Long-term investments:
Embedded Derivative
Cost	9,407,136,000	7,474,775,000
Ctrip.com International, Ltd. | Ctrip convertible debt securities | Long-term investments:
Embedded Derivative
Cost	$ 1,275,000,000	$ 1,250,000,000		$ 25,000,000	$ 500,000,000	$ 250,000,000	$ 500,000,000