Summary of Fair Value of Assets Acquired and Liabilities Assumed in Conjunction with Acquisition (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Mar. 08, 2013
Business Acquisition [Line Items]
Goodwill	$ 3,955,901		$ 3,663,674		$ 3,015,670
Wotif Group
Business Acquisition [Line Items]
Goodwill	350,093
Intangible assets with indefinite lives	125,762
Intangible assets with definite lives	138,292	[1]
Net assets (liabilities)	(43,429)	[2]
Deferred tax liabilities	(2,908)
Total	567,810
Trivago
Business Acquisition [Line Items]
Goodwill			633,436
Intangible assets with indefinite lives			220,416
Intangible assets with definite lives			136,281	[3]
Net assets (liabilities)			19,064	[4]
Deferred tax liabilities			(111,379)
Redeemable noncontrolling interest			(343,984)				(343,984)
Total			553,834
Travel management company
Business Acquisition [Line Items]
Goodwill					129,156
Intangible assets with definite lives					111,864	[5]
Net assets (liabilities)					(28,913)	[4]
Total					$ 212,107

[1] Acquired definite-lived intangible assets primarily consist of supplier contracts and customer relationships and have estimated useful lives of between less than one year and 10 years with a weighted average life of 7.8 years.

[2] Includes cash acquired of $36 million.

[3] Acquired definite-lived intangible assets primarily consist of technology, partner relationship and non-compete agreement assets and have estimated useful lives of between 3 and 7 years with a weighted average life of 3.7 years.

[4] Includes cash acquired of $13 million.

[5] Primarily consist of customer and supplier relationship assets with a weighted average life of 8.1 years.