Accumulated Other Comprehensive Income (Rollforward) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at December 31, 2017	$ (461.1)
Other comprehensive loss before reclassifications, net of tax	(8.4)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	2.1
Balance at March 31, 2018	(467.4)
Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at December 31, 2017	0.2
Other comprehensive loss before reclassifications, net of tax	(0.3)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0.9
Balance at March 31, 2018	0.8
Foreign Currency Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at December 31, 2017	(305.4)
Other comprehensive loss before reclassifications, net of tax	(4.3)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	0.0
Balance at March 31, 2018	(309.7)
Unrecognized Pension and Other Post-retirement Benefit Costs
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at December 31, 2017	(155.9)
Other comprehensive loss before reclassifications, net of tax	(3.8)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1.2
Balance at March 31, 2018	$ (158.5)