Derivatives/Hedges (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012
Commodity Derivatives [Member] | Designated as Hedging Instrument [Member] | Deferred Income Taxes and Other Current Assets [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Asset, Fair Value, Net,	$ 0	$ 156
Commodity Derivatives [Member] | Designated as Hedging Instrument [Member] | Accrued Expenses and Other Current Liabilities [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Net	0	924
Commodity Derivatives [Member] | Not Designated as Hedging Instrument [Member] | Accrued Expenses and Other Current Liabilities [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Liability, Fair Value, Net	4,265	2,606
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Deferred Income Taxes and Other Current Assets [Member]
Derivative, Fair Value, Net [Abstract]
Derivative Asset, Fair Value, Net,	$ 463	$ 205