Significant Accounting Policies, New Accounting Guidance, Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 394.9				$ 372.4					$ 394.9	$ 372.4
Net sales	566.6	$ 512.7	$ 508.3	$ 515.5	$ 488.3	$ 349.8	$ 317.7	$ 347.2		2,103.1	$ 1,503.0	$ 1,352.5
ASU 2014-09 [Member] | Maximum [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 1.0									$ 1.0
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | ASU 2014-09 [Member] | Forecast [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales									$ 3.0