Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity		$ 1,960.5			$ 1,960.5
Other comprehensive income (loss) before reclassifications					(21.9)
Amounts reclassified from accumulated other comprehensive loss					2.9
Other comprehensive (loss) income	$ 3.4		$ (2.3)		(19.0)	$ 6.0
Ending equity	1,973.5				1,973.5
Cash flow hedge (loss) gain
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity		(0.5)			(0.5)
Other comprehensive income (loss) before reclassifications					1.5
Amounts reclassified from accumulated other comprehensive loss					(0.6)
Other comprehensive (loss) income					0.9
Ending equity	0.4				0.4
Unrealized gain (loss) on available-for- sale securities
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity		0.6			0.6
Other comprehensive income (loss) before reclassifications					0.4
Amounts reclassified from accumulated other comprehensive loss					0.0
Other comprehensive (loss) income					0.4
Ending equity	1.0				1.0
Pension and post retirement benefit plan adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity		(203.2)			(203.2)
Other comprehensive income (loss) before reclassifications					0.0
Amounts reclassified from accumulated other comprehensive loss					3.5
Other comprehensive (loss) income					3.5
Ending equity	(199.7)				(199.7)
Cumulative translation adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity		(129.8)			(129.8)
Other comprehensive income (loss) before reclassifications					(23.8)
Amounts reclassified from accumulated other comprehensive loss					0.0
Other comprehensive (loss) income					(23.8)
Ending equity	(153.6)				(153.6)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning equity	(355.3)	(332.9)	(307.4)	$ (285.7)	(332.9)	(285.7)
Other comprehensive (loss) income	3.4	(22.4)	(2.3)	8.3
Ending equity	$ (351.9)	$ (355.3)	$ (309.7)	$ (307.4)	$ (351.9)	$ (309.7)