Goodwill and Intangible Assets, Net - Components of Intangible Assets with Definite Lives (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Cost	$ 2,285,209	$ 2,321,165
Accumulated Amortization	(1,295,629)	(987,065)
Net	989,580	1,334,100
Supplier relationships
Finite-Lived Intangible Assets [Line Items]
Cost	618,543	655,414
Accumulated Amortization	(289,834)	(223,666)
Net	328,709	431,748
Technology
Finite-Lived Intangible Assets [Line Items]
Cost	480,823	490,584
Accumulated Amortization	(355,471)	(258,261)
Net	125,352	232,323
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	622,117	613,277
Accumulated Amortization	(185,468)	(73,248)
Net	436,649	540,029
Domain names
Finite-Lived Intangible Assets [Line Items]
Cost	117,109	115,102
Accumulated Amortization	(53,607)	(34,758)
Net	63,502	80,344
Other
Finite-Lived Intangible Assets [Line Items]
Cost	446,617	446,788
Accumulated Amortization	(411,249)	(397,132)
Net	$ 35,368	$ 49,656