Goodwill and Intangible Assets - Carrying Amounts of Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 116,767
Additions due to acquisitions			1,589,990
Write-off of fully amortized intangible assets			(4,227)
Foreign currency translation impact			19,843
Gross cost, ending balance	$ 1,722,373		1,722,373
Accumulated amortization	(157,908)		(157,908)		$ (39,966)
Finite-lived intangible assets, net	1,564,465		1,564,465		76,801
Amortization of intangibles	51,224	$ 6,221	123,014	$ 18,614
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			63,369
Additions due to acquisitions			1,251,000
Write-off of fully amortized intangible assets			0
Foreign currency translation impact			12,073
Gross cost, ending balance	1,326,442		1,326,442
Accumulated amortization	(75,173)		(75,173)		(16,744)
Finite-lived intangible assets, net	1,251,269		$ 1,251,269		46,625
Customer Relationships | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			4 years
Customer Relationships | Maximum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			13 years
Software
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 16,025
Additions due to acquisitions			181,000
Write-off of fully amortized intangible assets			0
Foreign currency translation impact			1,194
Gross cost, ending balance	198,219		198,219
Accumulated amortization	(24,419)		(24,419)		(8,904)
Finite-lived intangible assets, net	173,800		$ 173,800		7,121
Software | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			3 years
Software | Maximum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			7 years
Content
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 3,728
Additions due to acquisitions			143,500
Write-off of fully amortized intangible assets			(4,227)
Foreign currency translation impact			6,080
Gross cost, ending balance	149,081		149,081
Accumulated amortization	(36,884)		(36,884)		(2,033)
Finite-lived intangible assets, net	112,197		$ 112,197		1,695
Content | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			1 year 6 months
Content | Maximum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			5 years
Other
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 33,645
Additions due to acquisitions			14,490
Write-off of fully amortized intangible assets			0
Foreign currency translation impact			496
Gross cost, ending balance	48,631		48,631
Accumulated amortization	(21,432)		(21,432)		(12,285)
Finite-lived intangible assets, net	$ 27,199		$ 27,199		$ 21,360
Other | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			2 years
Other | Maximum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			5 years