Net Earnings Per Share (Basic And Dilutive Net Earnings Per Share Reconciliations) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Schedule of Basic and Dilutive Net Earnings Per Share Reconciliation [Line Items]
Net earnings	$ 130,049us-gaap_NetIncomeLoss	$ 106,452us-gaap_NetIncomeLoss	$ 454,220us-gaap_NetIncomeLoss	$ 393,377us-gaap_NetIncomeLoss
Weighted average common shares outstanding	214,228	223,259	217,568	223,831
Weighted average common shares and dilutive potential common shares	217,025	227,417	220,585	227,870
Basic net earnings per share	$ 0.61us-gaap_EarningsPerShareBasic	$ 0.48us-gaap_EarningsPerShareBasic	$ 2.09us-gaap_EarningsPerShareBasic	$ 1.76us-gaap_EarningsPerShareBasic
Diluted net earnings per share	$ 0.60us-gaap_EarningsPerShareDiluted	$ 0.47us-gaap_EarningsPerShareDiluted	$ 2.06us-gaap_EarningsPerShareDiluted	$ 1.73us-gaap_EarningsPerShareDiluted
Stock Options [Member]
Schedule of Basic and Dilutive Net Earnings Per Share Reconciliation [Line Items]
Dilutive potential common shares	2,105	3,402	2,382	3,305
Stock-Settled Restricted Stock Units [Member]
Schedule of Basic and Dilutive Net Earnings Per Share Reconciliation [Line Items]
Dilutive potential common shares	692	756	635	734

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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