Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ Equity	$ 774,456
Balances attributable to Parent at Jul. 31, 2016		$ 22	$ 392,434	$ (109,194)	$ 491,194
Stockholders' Equity Attributable to Noncontrolling Interest at Jul. 31, 2016						$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	394,227	0	0	0	394,227
Net Income (Loss), Attributable to Noncontrolling Interest	34					34
Net income	394,261
Currency translation adjustment	8,518	0	0	8,518	0	0
Noncontrolling Interest, Increase from Business Combination	500	0	0	0	0	500
Exercise of stock options, net of repurchased shares	(104,245)	1	35,805	0	(140,051)	0
Employee stock-based compensation and related tax benefit	20,840	0	20,840	0	0	0
Shares issued for Employee Stock Purchase Plan	4,270	0	4,270	0	0	0
Stockholders' Equity Attributable to Noncontrolling Interest at Jul. 31, 2017						534
Balances attributable to Parent at Jul. 31, 2017		$ 23	453,349	(100,676)	745,370
Balances (in shares) at Jul. 31, 2016		220,244,120
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, net of repurchased shares (in shares)		10,053,463
Shares issued for Employee Stock Purchase Plan (in shares)		190,713
Balances (in shares) at Jul. 31, 2017		230,488,296
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ Equity	1,098,600
Net income	417,867	$ 0	0	0	417,867
Net Income (Loss), Attributable to Noncontrolling Interest	140					140
Net income	418,007
Currency translation adjustment	(7,252)	0	0	(7,252)	0	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(235)	0	0	0	0	(235)
Noncontrolling Interest, Decrease from Deconsolidation	(439)	0	0	0	0	(439)
Exercise of stock options, net of repurchased shares	43,344	0	44,459	0	(1,115)	0
Employee stock-based compensation and related tax benefit	23,221	0	23,197	0	24	0
Shares issued for Employee Stock Purchase Plan	5,853	0	5,853	0	0	0
Stockholders' Equity Attributable to Noncontrolling Interest at Jul. 31, 2018						0
Balances attributable to Parent at Jul. 31, 2018		$ 23	526,858	(107,928)	1,162,146
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, net of repurchased shares (in shares)		3,225,377
Shares issued for Employee Stock Purchase Plan (in shares)		185,168
Balances (in shares) at Jul. 31, 2018		233,898,841
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ Equity	1,581,099
Net income	591,693	$ 0	0	0	591,693
Net Income (Loss), Attributable to Noncontrolling Interest	0					0
Net income	591,693
Currency translation adjustment	(24,601)	0	0	(24,601)	0	0
Exercise of stock options, net of repurchased shares	(12,487)	0	32,500	0	(44,987)	0
Employee stock-based compensation and related tax benefit	23,445	0	23,445	0	0	0
Shares issued for Employee Stock Purchase Plan	7,183	0	7,183	0	0	0
Shares repurchased	(364,997)	0	(17,427)	0	(347,570)	0
Stockholders' Equity Attributable to Noncontrolling Interest at Jul. 31, 2019						$ 0
Balances attributable to Parent at Jul. 31, 2019		$ 23	$ 572,559	$ (132,529)	$ 1,338,328
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, net of repurchased shares (in shares)		3,349,980
Shares issued for Employee Stock Purchase Plan (in shares)		177,043
Shares repurchased (in shares)		(7,635,596)
Balances (in shares) at Jul. 31, 2019		229,790,268
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stockholders’ Equity	$ 1,778,381