Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	May 31, 2019	May 31, 2018	Feb. 28, 2019	Feb. 28, 2018
Changes in Stockholders' Equity
Beginning Balance	$ 1,613,932	$ 1,478,124
Net income	141,120	113,190
Other comprehensive income (loss), net of tax	(5,036)	(10,905)
Vest and exercise of share-based awards	369	875
Common stock repurchase	0	(150,019)
Share-based compensation expense	50,168	46,005
Minimum tax withholdings paid by the Company on behalf of employees related to net settlement of employee share-based awards	(81,274)	(77,094)
Re-issuance of treasury stock under employee stock purchase plan	39,937	32,211
Convertible note conversions	(1,296)	(835)
Exercise of convertible note hedges	16	0
Other adjustments	0
Cumulative Effect of New Accounting Principle in Period of Adoption		392
Ending Balance	1,757,936	1,431,944
Common Stock
Changes in Stockholders' Equity
Beginning Balance	$ 24	$ 24
Vest and exercise of share-based awards (shares)	944	905
Vest and exercise of share-based awards	$ 1
Convertible note conversions (shares)	943	185
Shares, Issued	246,290	239,779	244,403	238,689
Ending Balance	$ 25	$ 24
Additional Paid-In Capital
Changes in Stockholders' Equity
Beginning Balance	2,791,895	2,416,080
Vest and exercise of share-based awards	368	875
Common stock repurchase	0	(17,175)
Share-based compensation expense	50,168	46,005
Minimum tax withholdings paid by the Company on behalf of employees related to net settlement of employee share-based awards	(81,274)	(77,094)
Re-issuance of treasury stock under employee stock purchase plan	23,323	18,471
Convertible note conversions	(1,296)	(835)
Exercises of convertible note hedges	69,380	13,598
Other adjustments	(541)
Ending Balance	2,853,105	2,399,925
Retained Earnings
Changes in Stockholders' Equity
Beginning Balance	2,054,069	1,619,688
Net income	141,120	113,190
Cumulative Effect of New Accounting Principle in Period of Adoption		392
Ending Balance	2,195,189	1,733,270
Treasury Stock
Changes in Stockholders' Equity
Beginning Balance	(3,189,434)	(2,525,072)
Common stock repurchase	0	(132,844)
Re-issuance of treasury stock under employee stock purchase plan	16,614	13,740
Convertible note conversions	0
Exercises of convertible note hedges	(69,364)	(13,598)
Other adjustments	(541)
Ending Balance	(3,242,725)	(2,657,774)
Accumulated Other Comprehensive Loss
Changes in Stockholders' Equity
Beginning Balance	(42,622)	(32,596)
Other comprehensive income (loss), net of tax	(5,036)	(10,905)
Ending Balance	$ (47,658)	$ (43,501)