Financial Instruments and Fair Value Measurements - Narrative (Details) $ in Thousands, £ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2021 GBP (£) derivative	Jun. 30, 2021 USD ($) derivative	Dec. 31, 2020 USD ($)
Derivative [Line Items]
Aggregate notional amount						$ 2,059,700	$ 1,541,400
Net loss from derivatives not designated in hedging relationships	$ 16,000		$ 21,700
Foreign currency forwards | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of instruments | derivative					36	36
Aggregate notional amount					£ 136.9	$ 193,300	0
Currency exchange swaps | Not designated as hedging instrument
Derivative [Line Items]
Number of instruments | derivative					1	1
Aggregate notional amount					£ 672.5	$ 950,000	625,000
Interest rate swap | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of instruments | derivative					1	1
Aggregate notional amount						$ 250,000	250,000
Interest rate swap | Interest expense
Derivative [Line Items]
Unrealized gains (losses) reclassified to income statement	(2,600)	$ (3,700)	(5,100)	$ (5,300)
Interest rate swap unrealized loss expected to be reclassified within next twelve months						$ 10,300
Cross-currency swaps | Designated as hedging instrument | Cash flow hedge
Derivative [Line Items]
Number of instruments | derivative					4	4
Aggregate notional amount						$ 166,400	$ 166,400
Cross-currency swaps | Foreign exchange gains
Derivative [Line Items]
Unrealized gains (losses) reclassified to income statement	$ (200)	$ 800	$ (1,400)	$ 12,200
Cross-currency swap unrealized gains expected to be reclassified within next twelve months						$ 1,800