Business Combinations - Intangible Assets (Details) - DRG Acquisition - USD ($) $ in Thousands		9 Months Ended
	Feb. 28, 2020	Sep. 30, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	$ 487,400
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	381,000
Remaining Weighted - Average Amortization Period (in years)		17 years 7 months 6 days
Database and content
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	50,200
Remaining Weighted - Average Amortization Period (in years)		4 years 8 months 12 days
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	5,200
Remaining Weighted - Average Amortization Period (in years)		4 years
Purchased software
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	23,000
Remaining Weighted - Average Amortization Period (in years)		6 years 4 months 24 days
Backlog
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value as of February 28, 2020	$ 28,000
Remaining Weighted - Average Amortization Period (in years)		4 years