Goodwill and Intangible Assets, Net - Changes in Goodwill by Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 7,992,941	$ 3,955,901
Additions	128	4,243,133
Deductions		(72,693)
Foreign exchange translation		(133,400)
Foreign exchange translation and other	(51,046)
Goodwill, Ending Balance	7,942,023	7,992,941
Core OTA
Goodwill [Line Items]
Goodwill, Beginning Balance	4,717,371	3,133,495
Additions	128	1,633,711
Deductions		0
Foreign exchange translation		(49,835)
Foreign exchange translation and other	(14,028)
Goodwill, Ending Balance	4,703,471	4,717,371
trivago
Goodwill [Line Items]
Goodwill, Beginning Balance	539,577	593,419
Additions	0	6,241
Deductions		0
Foreign exchange translation		(60,083)
Foreign exchange translation and other	(23,339)
Goodwill, Ending Balance	516,238	539,577
Egencia
Goodwill [Line Items]
Goodwill, Beginning Balance	133,281	156,324
Deductions		0
Foreign exchange translation		(23,043)
Foreign exchange translation and other	(1,552)
Goodwill, Ending Balance	131,729	133,281
HomeAway
Goodwill [Line Items]
Goodwill, Beginning Balance	2,602,712
Additions	0	2,602,712
Deductions		0
Foreign exchange translation and other	(12,127)
Goodwill, Ending Balance	2,590,585	2,602,712
eLong
Goodwill [Line Items]
Goodwill, Beginning Balance	0	72,663
Additions	0	469
Deductions		(72,693)
Foreign exchange translation		(439)
Foreign exchange translation and other	$ 0
Goodwill, Ending Balance		$ 0