Fair Value Measurements (Schedule Of Items Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2013	Feb. 28, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	$ 682,266	$ 461,260
Mutual fund investments	5,821	4,024
Total assets at fair value	688,087	465,284
Percent of total assets at fair value	100.00%	100.00%
Percent of total assets	6.10%	4.70%
Derivative instruments	2,889	517
Total liabilities at fair value	2,889	517
Percent of total liabilities	0.00%	0.00%
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	682,266	461,260
Mutual fund investments	5,821	4,024
Total assets at fair value	688,087	465,284
Percent of total assets at fair value	100.00%	100.00%
Percent of total assets	6.10%	4.70%
Derivative instruments	0	0
Total liabilities at fair value	0	0
Percent of total liabilities	0.00%	0.00%
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market securities	0	0
Mutual fund investments	0	0
Total assets at fair value	0	0
Percent of total assets at fair value	0.00%	0.00%
Percent of total assets	0.00%	0.00%
Derivative instruments	2,889	517
Total liabilities at fair value	$ 2,889	$ 517
Percent of total liabilities	0.00%	0.00%