STOCK-BASED EMPLOYEE COMPENSATION (Schedule of Assumed Stock Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Number of Shares
Exercised (in shares)	(2,250)
Ending balance (in shares)	6,750
Weighted Average Exercise Price
Exercised (in dollars per share)	$ 22.25
Ending balance (in dollars per share)	$ 22.66
Aggregate Intrinsic Value	$ 7,900
Vested and exercisable as of March 31, 2014
Weighted Average Remaining Contractual Term	1 year
KAYAK [Member]
Number of Shares
Beginning balance (in shares)	128,708
Exercised (in shares)	(23,809)
Forfeited (in shares)	(147)
Ending balance (in shares)	104,752	128,708
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 335.83
Exercised (in dollars per share)	$ 313.57
Forfeited (in dollars per share)	$ 452.45
Ending balance (in dollars per share)	$ 340.73	$ 335.83
Aggregate Intrinsic Value	89,161	106,386
Weighted Average Remaining Contractual Term	6 years 8 months	6 years 11 months
Vested and exercisable as of March 31, 2014
Number of Shares	72,009
Weighted Average Exercise Price (in dollars per share)	$ 268.68
Aggregate Intrinsic Value	66,479
Weighted Average Remaining Contractual Term	6 years
Vested and exercisable as of March 31, 2014 and expected to vest thereafter, net of estimated forfeitures
Number of Shares	103,203
Weighted Average Exercise Price (in dollars per share)	$ 337.72
Aggregate Intrinsic Value	$ 88,153
Weighted Average Remaining Contractual Term	6 years 8 months