Shareholders' Equity - Reclassification out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Loss	$ (0.2)	$ 0.1
Amortization of net actuarial loss | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Loss	0.1	0.1
Cumulative translation adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Loss	0.0
Cumulative translation adjustment | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Loss	$ (0.3)	$ 0.0