Financial Risk Management and Derivatives (Details) (USD $)					3 Months Ended		6 Months Ended
	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2013 Forward Foreign Currency Exchange Contracts [Member]	Mar. 31, 2013 Forward Foreign Currency Exchange Contracts [Member]	Sep. 30, 2013 Forward Foreign Currency Exchange Contracts [Member] General and Administrative Expenses [Member]	Sep. 30, 2012 Forward Foreign Currency Exchange Contracts [Member] General and Administrative Expenses [Member]	Sep. 30, 2013 Forward Foreign Currency Exchange Contracts [Member] General and Administrative Expenses [Member]	Sep. 30, 2012 Forward Foreign Currency Exchange Contracts [Member] General and Administrative Expenses [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount of foreign currency derivatives			$ 16,749,000	$ 17,543,000
Forward foreign currency exchange contracts					(100,000)	431,000	(833,000)	340,000
Forward foreign currency exchange contracts included in other current liabilities	150,000
Forward foreign currency exchange contracts included in prepaid expenses and other current assets		$ 683,000