Other Intangible Assets, net and Goodwill - Other Intangible Assets, net (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	$ 2,867,332	$ 2,323,087
Finite-lived intangible assets, Accumulated Amortization	(811,495)	(658,875)
Total finite-lived intangible assets	2,055,837	1,664,212
Intangible assets, Gross	3,028,722	2,487,515
Total intangible assets	2,217,227	1,828,640
Trade names
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	161,390	164,428
Customer relationships
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	651,647	280,493
Finite-lived intangible assets, Accumulated Amortization	(194,003)	(180,571)
Total finite-lived intangible assets	457,644	99,922
Databases and content
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	1,829,563	1,755,323
Finite-lived intangible assets, Accumulated Amortization	(431,393)	(342,385)
Total finite-lived intangible assets	1,398,170	1,412,938
Computer software
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	351,262	285,701
Finite-lived intangible assets, Accumulated Amortization	(181,166)	(135,919)
Total finite-lived intangible assets	170,096	149,782
Trade names
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	6,770	1,570
Finite-lived intangible assets, Accumulated Amortization	(830)	0
Total finite-lived intangible assets	5,940	$ 1,570
Backlog
Goodwill And Intangible Assets [Line Items]
Finite-lived intangible assets, Gross	28,090
Finite-lived intangible assets, Accumulated Amortization	(4,103)
Total finite-lived intangible assets	$ 23,987