Fair Value Measurements (Schedule Of Items Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Thousands	Nov. 30, 2016	Feb. 29, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	$ 460,379	$ 439,943
Mutual fund investments	17,861	13,622
Derivative instruments	8,778	587
Total assets at fair value	$ 487,018	$ 454,152
Percent of total assets at fair value	100.00%	100.00%
Percent of total assets	3.10%	3.10%
Liabilities: Derivative instruments	$ (318)	$ (8,024)
Total liabilities at fair value	$ (318)	$ (8,024)
Percent of total liabilities	0.00%	0.10%
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	$ 460,379	$ 439,943
Mutual fund investments	17,861	13,622
Derivative instruments	0	0
Total assets at fair value	$ 478,240	$ 453,565
Percent of total assets at fair value	98.20%	99.90%
Percent of total assets	3.00%	3.10%
Liabilities: Derivative instruments	$ 0	$ 0
Total liabilities at fair value	$ 0	$ 0
Percent of total liabilities	0.00%	0.00%
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	$ 0	$ 0
Mutual fund investments	0	0
Derivative instruments	8,778	587
Total assets at fair value	$ 8,778	$ 587
Percent of total assets at fair value	1.80%	0.10%
Percent of total assets	0.10%	0.00%
Liabilities: Derivative instruments	$ (318)	$ (8,024)
Total liabilities at fair value	$ (318)	$ (8,024)
Percent of total liabilities	0.00%	0.10%