Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (103.9)		$ (128.4)
Other comprehensive income before reclassifications	1.5		(4.3)
Reclassifications [Abstract]
Total other comprehensive (loss) income	2.4		(2.9)
Ending balance	(101.5)		(131.3)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications [Abstract]
Amortization of unrecognized net loss	1.4	[1]	1.6	[1]
Amortization of unrecognized prior service credit			(0.3)	[1]
Commodity derivatives			0.1	[2]
Income taxes	(0.5)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	27.3		17.8
Other comprehensive income before reclassifications	1.5		(4.3)
Reclassifications [Abstract]
Total other comprehensive (loss) income	1.5		(4.3)
Ending balance	28.8		13.5
Foreign Currency Translation [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications [Abstract]
Amortization of unrecognized net loss	0	[1]	0	[1]
Amortization of unrecognized prior service credit			0	[1]
Commodity derivatives			0	[2]
Income taxes	0
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	0		(1.1)
Other comprehensive income before reclassifications	0		0
Reclassifications [Abstract]
Total other comprehensive (loss) income	0		0.1
Ending balance	0		(1.0)
Cash Flow Hedges [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications [Abstract]
Amortization of unrecognized net loss	0	[1]	0	[1]
Amortization of unrecognized prior service credit			0	[1]
Commodity derivatives			0.1	[2]
Income taxes	0
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(131.2)		(145.1)
Other comprehensive income before reclassifications	0		0
Reclassifications [Abstract]
Total other comprehensive (loss) income	0.9		1.3
Ending balance	(130.3)		(143.8)
Defined Benefit Plans [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications [Abstract]
Amortization of unrecognized net loss	1.4	[1]	1.6	[1]
Amortization of unrecognized prior service credit			(0.3)	[1]
Commodity derivatives			0	[2]
Income taxes	$ (0.5)

[1] Amounts are included in the calculation of net periodic benefit cost. See Note 4 for additional information.

[2] Reclassifications for commodity derivatives are included in cost of sales.