Business Acquisition (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020
Business Combinations [Abstract]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		13 years
Goodwill, Acquired During Period		$ 217,608
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 160,000	160,000
Business Acquisition [Line Items]
Goodwill	1,126,843	1,126,843	$ 914,520
Kantar Health
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	14,992	14,992
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	31,952	31,952
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	11,776	11,776
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	1,147	1,147
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Right-of-use Assets	1,680	1,680
Goodwill	217,608	217,608
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets	26	26
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable	(36,143)	(36,143)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue	(35,640)	(35,640)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Accrued Payroll and Tax Withholdings	(11,031)	(11,031)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other	(3,777)	(3,777)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent	(10,169)	(10,169)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	(10,250)	(10,250)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	365,171	$ 365,171
Business Acquisition, Effective Date of Acquisition		Apr. 01, 2021
Business Acquisition, Description of Acquired Entity		we acquired Kantar Health, a division of Kantar Group. Kantar Health provides data, analytics, commercial research, and consulting services to the life sciences industry.
Business Combination, Reason for Business Combination		We believe this acquisition complements our existing Data-as-a-Service efforts as it provides a meaningful entry into the pharmaceutical market through Kantar Health's existing clients and their leadership team with important industry experience and relationships.
Business Combination, Goodwill Recognized, Description		These factors, combined with the synergies and economies of scale expected, are the basis for the acquisition and comprise the resulting goodwill recorded.
Business Combination, Consideration Transferred		$ 375,000
Business Acquisition, Date of Acquisition Agreement		Dec. 16, 2020
Business Combination, Provisional Information, Initial Accounting Incomplete, Reasons		The allocation of purchase price is preliminary and subject to changes, as appraisals of intangible assets are finalized, working capital and certain other adjustments are agreed upon, and additional information becomes available.
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	45,000	$ 90,000
Kantar Health | Trade Names
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	10,200	10,200
Kantar Health | Customer Relationships
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	143,100	143,100
Kantar Health | Technology-Based Intangible Assets
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 39,700	$ 39,700