Summary of Significant Accounting Policies (Details 1) - $ / shares	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, method used	The fair value of each option, without a market-based condition was estimated on the measurement date using the Black-Scholes Merton (“BSM”) option-pricing model. For options that included a market-based condition the Monte Carlo simulation model was used. The Black-Scholes Merton option-pricing model utilized the following assumptions:July 31,202020192018Expected life (in years)5.4—5.75.3—6.65.3—6.9Risk-free interest rate0.29 %—1.67 %1.80 %—2.69 %1.88 %—2.62 %Estimated volatility21.7%—27.6%21.6%—22.1%19.7%—20.7%Expected dividends— %— %— %Weighted average fair value at measurement date$21.54 $15.47 $8.88
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, method used	Black-Scholes Merton option-pricing model	Black-Scholes Merton option-pricing model	Black-Scholes Merton option-pricing model
Risk-free interest rate, minimum	0.29%	1.80%	1.88%
Risk-free interest rate, maximum	1.67%	2.69%	2.62%
Estimated volatility, minimum	21.70%	21.60%	19.70%
Estimated volatility, maximum	27.60%	22.10%	20.70%
Expected dividends	0.00%	0.00%	0.00%
Weighted average fair value at measurement date (in dollars per share)	$ 21.54	$ 15.47	$ 8.88
Stock Options | Valuation Technique, Option Pricing Model [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, method used	Monte Carlo simulation model
Risk-free interest rate, minimum	0.71%
Estimated volatility, minimum	25.20%
Expected dividends	0.00%
Weighted average fair value at measurement date (in dollars per share)	$ 24.89
Minimum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	5 years 4 months 24 days	5 years 3 months 18 days	5 years 3 months 18 days
Minimum | Stock Options | Valuation Technique, Option Pricing Model [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	7 years 7 months 20 days
Maximum | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	5 years 8 months 12 days	6 years 7 months 6 days	6 years 10 months 24 days