Indebtedness (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Dec. 31, 2012	Mar. 31, 2012
Debt Instrument [Line Items]
Short-term debt	$ 26.2	$ 21.3
Long-term debt, fair value	143.0	139.0
Line of Credit Facility [Line Items]
Available for future borrowings	191.0
Domestic Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Amount outstanding	0	9.0
Maximum borrowing capacity	145.0
Expiration date	Aug. 31, 2014
Available for future borrowings	139.0
Foreign Credit Facility [Member]
Line of Credit Facility [Line Items]
Available for future borrowings	52.0
Letters of Credit [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	6.0
6.83% Senior Notes [Member]
Debt Instrument [Line Items]
Long-term debt	$ 125.0
Stated interest rate (in hundredths)	6.83%
Maturity date	Aug. 12, 2020