Supplemental Balance Sheet Data - AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period	$ 406.3	$ 390.2
Other comprehensive income (loss) before reclassifications	(4.0)
Amounts reclassified from AOCI	1.6
Other comprehensive loss, including income taxes	(2.4)	(1.5)
Provision (benefit) for income taxes	0.2	0.2
Other comprehensive income (loss)	(2.6)	(1.7)
Balance at the end of the period	409.8	394.2
Income tax benefit	(4.3)	(2.4)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified from AOCI	1.6	1.7
Income tax benefit	0.5	0.4
Net Unrealized Foreign Currency Translation Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period	(19.0)
Other comprehensive income (loss) before reclassifications	(4.0)
Amounts reclassified from AOCI	0.0
Other comprehensive loss, including income taxes	(4.0)
Provision (benefit) for income taxes	(0.3)
Other comprehensive income (loss)	(3.7)
Balance at the end of the period	(22.7)
Net Loss from Pension and Other Postretirement Liabilities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period	(94.3)
Other comprehensive income (loss) before reclassifications	0.0
Amounts reclassified from AOCI	1.6
Other comprehensive loss, including income taxes	1.6
Provision (benefit) for income taxes	0.5
Other comprehensive income (loss)	1.1
Balance at the end of the period	(93.2)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at the beginning of the period	(113.3)	(105.1)
Other comprehensive income (loss)	(2.6)	(1.7)
Balance at the end of the period	$ (115.9)	$ (106.8)