Defined Contribution Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
UNITED STATES
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 33.0	$ 32.4	$ 32.4
Supplemental matching	7.7	9.1	6.8
United Kingdom Subsidiary | UK Plan
Defined Contribution Plan Disclosure [Line Items]
Expense recognized	$ 8.3	$ 7.4	$ 6.1