Derivative Financial Instruments (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Costs of revenue
Derivative Financial Instruments
Amount of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	$ (1,080)	$ (681)	$ (3,890)	$ (214)
Operating expenses
Derivative Financial Instruments
Amount of Gain (Loss) Reclassified from AOCI into Income (Effective Portion)	(583)	(346)	(2,126)	(123)
Derivatives Designated as Cash Flow Hedging Relationships | Foreign currency exchange contracts
Derivative Financial Instruments
Amount of Gain (Loss) Recognized in AOCI on Derivative (Effective Portion)	(2,951)	(8,166)	(4,789)	(13,564)
Derivatives not Designated as Hedging Instrument | Foreign currency exchange contracts | Costs of revenue
Derivative Financial Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	14	76	119	198
Derivatives not Designated as Hedging Instrument | Foreign currency exchange contracts | Foreign currency transaction gains (losses)
Derivative Financial Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	(429)	(880)	(904)	(2,091)
Derivatives not Designated as Hedging Instrument | Foreign currency exchange contracts | Revenue
Derivative Financial Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives	(23)	(133)	(172)	(334)
Derivatives not Designated as Hedging Instrument | Foreign currency exchange contracts | Selling, general and administrative expenses
Derivative Financial Instruments
Amount of Gain (Loss) Recognized in Income on Derivatives		$ 6	$ 11	$ 12