Changes in Goodwill by Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, Beginning Balance	$ 3,955,901	$ 3,663,674
Additions	4,243,133	418,408
Deductions	(72,693)
Foreign exchange translation	(133,400)	(126,181)
Goodwill, Ending Balance	7,992,941	3,955,901
Core OTAs
Goodwill [Line Items]
Goodwill, Beginning Balance	3,133,495	2,781,296
Additions	1,633,711	402,752
Foreign exchange translation	(49,835)	(50,553)
Goodwill, Ending Balance	4,717,371	3,133,495
Trivago
Goodwill [Line Items]
Goodwill, Beginning Balance	593,419	633,436
Additions	6,241	1,045
Foreign exchange translation	(60,083)	(41,062)
Goodwill, Ending Balance	539,577	593,419
Egencia
Goodwill [Line Items]
Goodwill, Beginning Balance	156,324	194,651
Foreign exchange translation	(23,043)	(38,327)
Goodwill, Ending Balance	133,281	156,324
Home Away Inc
Goodwill [Line Items]
Additions	2,602,712
Goodwill, Ending Balance	2,602,712
eLong, Inc
Goodwill [Line Items]
Goodwill, Beginning Balance	72,663	54,291
Additions	469	14,611
Deductions	(72,693)
Foreign exchange translation	$ (439)	3,761
Goodwill, Ending Balance		$ 72,663