Goodwill and Intangible Assets - Carrying Amounts of Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			$ 1,301,120
Intangible assets fully amortized			(13,138)
Foreign currency translation impact			(12,032)
Gross cost, ending balance	$ 1,275,950		1,275,950
Accumulated amortization	(454,956)		(454,956)		$ (376,033)
Finite-lived intangible assets, net	820,994		820,994		925,087
Amortization of intangibles	31,228	$ 31,694	94,615	$ 97,541
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance			1,145,109
Intangible assets fully amortized			(1,650)
Foreign currency translation impact			(11,339)
Gross cost, ending balance	1,132,120		1,132,120
Accumulated amortization	(351,738)		(351,738)		(283,369)
Finite-lived intangible assets, net	780,382		$ 780,382		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			(375)
Gross cost, ending balance	109,871		109,871
Accumulated amortization	(77,239)		(77,239)		(61,564)
Finite-lived intangible assets, net	32,632		$ 32,632		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			(9,929)
Foreign currency translation impact			(246)
Gross cost, ending balance	3,965		3,965
Accumulated amortization	(3,177)		(3,177)		(11,225)
Finite-lived intangible assets, net	788		$ 788		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	(22,802)		(22,802)		(19,875)
Finite-lived intangible assets, net	$ 7,192		$ 7,192		$ 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