Supplemental Balance Sheet Data - AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 316.0	$ 367.6
Other comprehensive income (loss) before reclassifications	(8.1)
Amounts reclassified from AOCI	1.0
Income (loss) from other comprehensive income items	(7.1)	(7.4)
Provision (benefit) for income taxes	0.0	0.0
Other comprehensive income (loss)	(7.1)	(7.4)
Ending balance	307.8	361.6
Net Unrealized Foreign Currency Translation Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(25.2)
Other comprehensive income (loss) before reclassifications	(8.1)
Amounts reclassified from AOCI	0.0
Income (loss) from other comprehensive income items	(8.1)
Provision (benefit) for income taxes	(0.3)
Other comprehensive income (loss)	(7.8)
Ending balance	(33.0)
Net Loss from Pension and Other Postretirement Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(71.7)
Other comprehensive income (loss) before reclassifications	0.0
Amounts reclassified from AOCI	1.0
Income (loss) from other comprehensive income items	1.0
Provision (benefit) for income taxes	0.3
Other comprehensive income (loss)	0.7
Ending balance	(71.0)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(96.9)	(103.7)
Other comprehensive income (loss)	(7.1)	(7.4)
Ending balance	$ (104.0)	$ (111.1)