Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Disaggregation of Revenue [Line Items]
Service revenues and vehicle sales	$ 867,460	$ 617,031	$ 1,677,592	$ 1,209,971
Service revenues
Disaggregation of Revenue [Line Items]
Service revenues and vehicle sales	711,090	532,601	1,378,908	1,047,973
Vehicle sales
Disaggregation of Revenue [Line Items]
Service revenues and vehicle sales	$ 156,370	$ 84,430	$ 298,684	$ 161,998