Stock and Stock-Based Incentive Plans Stock and Stock-Based Incentive Plans (Composition of Share-Based Compensation Expense - By Grant Type) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	$ 16,113	$ 11,769	$ 53,493	$ 73,096
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	5,125	4,756	21,411	32,977
Cash-settled restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	8,450	4,490	21,353	25,951
Stock-settled market stock units (MSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	2,135	2,463	8,299	9,811
Stock-settled performance stock units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	59	(488)	549	1,844
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	335	305	1,130	1,070
Restricted stock awards (RSAs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense, before income taxes	$ 9	$ 243	$ 751	$ 1,443