Acquisitions and Other Investments - Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 17, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 8,027,179		$ 8,027,179		$ 7,992,941
Revenue		2,580,905	$ 1,937,753	6,680,735	$ 4,973,750
Operating income (loss)		386,152	344,998	314,516	384,089
Core OTA
Business Acquisition [Line Items]
Revenue		$ 2,083,393	1,739,363	$ 5,388,178	4,372,224
Orbitz Worldwide, Inc.
Business Acquisition [Line Items]
Total purchase consideration	$ 1,813,524
Cash consideration	$ 1,362,362
Acquisition price paid per share	$ 12
Pre-existing debt extinguished	$ 432,231
Fair value of stock-based compensation awards granted	16,717
Stock-based compensation expense not yet recognized	49,000
Stock-based compensation expense recognized						$ 34,000
Goodwill	1,454,335
Revenue			19,000		19,000
Operating income (loss)			(86,000)		(86,000)
Contingent consideration payable upon closing	25,000
Continuity incentive offerred	30,000
Acquisition related expenses			$ 6,000		$ 16,000
Orbitz Worldwide, Inc. | Core OTA
Business Acquisition [Line Items]
Goodwill	$ 1,500,000