Commitments and Contingencies - Contingencies (Details) - USD ($) $ in Thousands			3 Months Ended	12 Months Ended
	Oct. 01, 2020	Feb. 28, 2020	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 15, 2018	Jun. 01, 2017
Commitments and Contingencies
Contingent purchase price paid				$ 7,816	$ 2,371	$ 2,470
Write off of accumulated foreign currency impacts			$ 33,819
Newly issued ordinary shares (in shares)				2,895,638
Recurring
Commitments and Contingencies
Contingent stock liability				$ 130,594
Level 3 | Recurring
Commitments and Contingencies
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Payment Earn Out Liability				(8,000)
Publons
Commitments and Contingencies
Additional payments to acquire business								$ 9,500
Contingent stock liability			2,960	0	3,100	2,960
Kopernio
Commitments and Contingencies
Additional payments to acquire business				2,184			$ 3,500
Contingent purchase price paid				3,701
TrademarkVision
Commitments and Contingencies
Contingent stock liability			$ 4,115	0	$ 8,000	$ 4,115
Decision Resources Group
Commitments and Contingencies
Additional payments to acquire business		$ 58,897		86,029
Contingent stock liability		$ 58,897
Increase in contingent consideration				$ 27,132
Newly issued ordinary shares (in shares)		2,895,638		2,895,638
CPA Global
Commitments and Contingencies
Additional payments to acquire business				$ 44,565
Contingent stock liability	$ 46,485
Increase in contingent consideration				$ (1,920)
Newly issued ordinary shares (in shares)	218,183,778			1,500,000