Other Comprehensive Loss - Components of Accumulated Comprehensive Income (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ 592.0	$ 597.7	$ 562.1	$ 557.9
Accumulated other comprehensive loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(138.3)	(122.6)	$ (123.8)	$ (124.5)
Net gain (loss) on pension and OPEB liability adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(23.8)	(24.3)
Accumulated other comprehensive loss, tax benefit	12.6	12.8
Unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(16.2)	(3.5)
Accumulated other comprehensive loss, tax benefit	4.4	1.6
Unrealized (loss) gain on foreign currency translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(98.3)	(94.8)
Accumulated other comprehensive loss, tax benefit	$ 5.7	$ 5.0