Segments and Other Geographic Reporting Segment Reporting (Details) $ in Thousands	3 Months Ended
	Oct. 31, 2020 USD ($) Segment	Oct. 31, 2019 USD ($)	Jul. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | Segment	2
Number of Reportable Segments | Segment	2
Service revenues and vehicle sales:	$ 592,940	$ 554,424
Yard operations	231,811	240,791
Cost of vehicle sales	64,360	58,764
General and administrative	48,175	49,478
Operating income	248,594	205,391
Depreciation and amortization	28,949	23,014
Capital expenditures, including acquisitions	147,093	131,793
Total assets	3,741,188		$ 3,455,261
Goodwill	342,576		343,622
Operating Segments | United States | United States
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	497,255	464,164
Yard operations	194,419	204,830
Cost of vehicle sales	41,506	31,072
General and administrative	38,091	39,212
Operating income	223,239	189,050
Depreciation and amortization	26,105	20,567
Capital expenditures, including acquisitions	122,459	113,266
Total assets	3,161,943		2,901,158
Goodwill	262,423		262,423
Operating Segments | International | International
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	95,685	90,260
Yard operations	37,392	35,961
Cost of vehicle sales	22,854	27,692
General and administrative	10,084	10,266
Operating income	25,355	16,341
Depreciation and amortization	2,844	2,447
Capital expenditures, including acquisitions	24,634	18,527
Total assets	579,245		554,103
Goodwill	80,153		$ 81,199
Service revenues
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	515,372	487,856
Service revenues | Operating Segments | United States | United States
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	450,235	430,803
Service revenues | Operating Segments | International | International
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	65,137	57,053
Vehicle sales
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	77,568	66,568
Vehicle sales | Operating Segments | United States | United States
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	47,020	33,361
Vehicle sales | Operating Segments | International | International
Segment Reporting Information [Line Items]
Service revenues and vehicle sales:	$ 30,548	$ 33,207