Foreign Currency Transactions and Derivatives (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Mar. 31, 2011
Foreign Currency Transactions and Derivatives [Abstract]
Foreign currency net gain (loss) resulting from anticipated transactions and inter-company balances	$ 1,500,000	$ (1,200,000)	$ 569,000	$ (666,000)
Hedging transaction net gain (loss) from foreign exchange derivative contracts	(332,000)	106,000	(588,000)	19,000
Amount of derivative contracts to sell	1,700,000		1,700,000		3,300,000
Amount of derivative contracts to purchase	$ 10,300,000		$ 10,300,000		$ 5,700,000