Goodwill and Intangible Assets - Carrying Amounts of Amortizable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance	$ 1,279,386
Foreign currency translation impact	1,001
Gross cost, ending balance	1,280,387
Accumulated amortization	(502,946)		$ (472,388)
Finite-lived intangible assets, net	777,441		806,998
Amortization of intangibles	30,514	$ 32,179
Customer Relationships
Finite-lived Intangible Assets [Roll Forward]
Gross cost, beginning balance	1,154,210
Foreign currency translation impact	948
Gross cost, ending balance	1,155,158
Accumulated amortization	(406,074)		(381,776)
Finite-lived intangible assets, net	$ 749,084		772,434
Customer Relationships | Minimum
Finite-lived Intangible Assets [Roll Forward]
Finite-lived intangible assets useful life	6 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	$ 110,597
Foreign currency translation impact	53
Gross cost, ending balance	110,650
Accumulated amortization	(88,933)		(83,320)
Finite-lived intangible assets, net	$ 21,717		27,277
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	$ 3,965
Foreign currency translation impact	0
Gross cost, ending balance	3,965
Accumulated amortization	(3,965)		(3,595)
Finite-lived intangible assets, net	$ 0		370
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	$ 10,614
Foreign currency translation impact	0
Gross cost, ending balance	10,614
Accumulated amortization	(3,974)		(3,697)
Finite-lived intangible assets, net	$ 6,640		$ 6,917
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