Derivative and Other Financial Instruments Foreign Currency Contracts (Details) (Foreign Exchange Contract [Member], Fair Value Hedging [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ 5,994	$ 5,774	$ 15,088
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	6,033	5,679	11,448
General and Administrative Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Income	$ (39)	$ 95	$ 3,640