Accumulated Other Comprehensive Loss - Details of Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 172.5
Other comprehensive (loss) income before reclassifications			13.1	$ (83.8)
Less: amounts reclassified from accumulated other comprehensive loss	$ 2.1	$ (0.5)	5.6	(0.2)
Other comprehensive income (loss)	24.8	25.3	18.7	(84.0)
Ending balance	93.8		93.8
Unrecognized Pension Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(172.5)	(146.1)
Other comprehensive (loss) income before reclassifications			(1.2)	(0.1)
Less: amounts reclassified from accumulated other comprehensive loss			2.7	2.2
Other comprehensive income (loss)			1.5	2.1
Ending balance	(171.0)	(144.0)	(171.0)	(144.0)
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(721.7)	(728.6)
Other comprehensive (loss) income before reclassifications			2.0	(87.1)
Less: amounts reclassified from accumulated other comprehensive loss			0.0	0.0
Other comprehensive income (loss)			2.0	(87.1)
Ending balance	(719.7)	(815.7)	(719.7)	(815.7)
Cumulative Translation Adjustment | Intra-entity transactions
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Intra-entity currency translation adjustment in AOCI	(12.0)	4.5	(12.0)	4.5
Unrecognized (Losses) Gains on Derivative Instruments | Net investment hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(67.5)	(34.5)
Other comprehensive (loss) income before reclassifications			12.1	(1.3)
Less: amounts reclassified from accumulated other comprehensive loss			0.0	0.0
Other comprehensive income (loss)			12.1	(1.3)
Ending balance	(55.4)	(35.8)	(55.4)	(35.8)
Unrecognized (Losses) Gains on Derivative Instruments | Cash Flow Hedge
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(1.8)	0.2
Other comprehensive (loss) income before reclassifications			0.2	4.7
Less: amounts reclassified from accumulated other comprehensive loss			2.9	(2.4)
Other comprehensive income (loss)			3.1	2.3
Ending balance	1.3	2.5	1.3	2.5
Accumulated Other Comprehensive Loss, Net of  Taxes
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(963.5)	(909.0)
Ending balance	$ (944.8)	$ (993.0)	$ (944.8)	$ (993.0)