Fair Value Measurement Of Assets And Liabilities (Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands	Sep. 30, 2011	Mar. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Liabilities	$ (2,144,012)	$ (2,199,061)
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	1,503,659	859,831
Total Liabilities	(57,367)	(6,900)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	430,998	399,831
Total Liabilities	(57,367)	(6,900)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Money Market Funds And Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	404,505	375,760
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	26,493	24,071
Total Liabilities	(57,367)	(6,900)
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	1,072,661	460,000
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Deferred Purchase Price Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	1,072,661	460,000
Fair Value, Measurements, Recurring [Member] | Money Market Funds And Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	404,505	375,760
Fair Value, Measurements, Recurring [Member] | Deferred Purchase Price Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	1,072,661	460,000
Fair Value, Measurements, Recurring [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total Assets	26,493	24,071
Total Liabilities	$ (57,367)	$ (6,900)