Goodwill and Intangible Assets - Carrying Amounts of Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 1,301,120
Intangible assets fully amortized			(11,559)
Foreign currency translation impact			(18,594)
Gross cost, ending balance	$ 1,270,967		1,270,967
Accumulated amortization	(423,592)		(423,592)		$ (376,033)
Finite-lived intangible assets, net	847,375		847,375		925,087
Amortization of intangibles	31,208	$ 32,164	63,387	$ 65,847
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			1,145,109
Intangible assets fully amortized			0
Foreign currency translation impact			(17,773)
Gross cost, ending balance	1,127,336		1,127,336
Accumulated amortization	(327,640)		(327,640)		(283,369)
Finite-lived intangible assets, net	799,696		$ 799,696		861,740
Customer Relationships | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			3 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			$ 111,033
Intangible assets fully amortized			(787)
Foreign currency translation impact			(574)
Gross cost, ending balance	109,672		109,672
Accumulated amortization	(71,574)		(71,574)		(61,564)
Finite-lived intangible assets, net	38,098		$ 38,098		49,469
Software | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			2 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			$ 14,140
Intangible assets fully amortized			(10,000)
Foreign currency translation impact			(175)
Gross cost, ending balance	3,965		3,965
Accumulated amortization	(2,758)		(2,758)		(11,225)
Finite-lived intangible assets, net	1,207		$ 1,207		2,915
Content | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			2 years
Content | Maximum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life			3 years
Other
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 30,838
Intangible assets fully amortized			(772)
Foreign currency translation impact			(72)
Gross cost, ending balance	29,994		29,994
Accumulated amortization	(21,620)		(21,620)		(19,875)
Finite-lived intangible assets, net	$ 8,374		$ 8,374		$ 10,963
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			11 years