Segments and Other Geographic Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Jul. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments			2
Number of Reportable Segments			2
Total service revenues and vehicle sales	$ 373,862	$ 347,246	$ 1,069,385	$ 935,790
Yard operations	166,572	151,855	503,264	428,729
Cost of vehicle sales	34,785	37,744	101,558	103,939
General and administrative	35,717	35,699	114,071	102,843
Operating income	136,788	121,948	350,492	300,279
Interest (expense) income, net	(5,506)	(5,419)	(16,888)	(15,900)
Other (expense) income, net	(194)	39	117	5,501
Intercompany income (expense)	0	0	0	0
Income before income taxes	131,088	116,568	333,721	289,880
Income taxes	40,542	41,944	9,829	103,642
Net income	90,546	74,624	323,892	186,238
Depreciation and amortization	13,208	12,358	43,132	35,570
Capital expenditures, including acquisitions	42,298	66,070	134,710	143,833
Total assets	1,811,686		1,811,686		$ 1,649,820
Goodwill	258,634		258,634		260,198
Operating Segments | United States | United States
Segment Reporting Information [Line Items]
Total service revenues and vehicle sales	307,120	279,210	879,093	747,936
Yard operations	142,631	128,839	435,179	363,089
Cost of vehicle sales	15,009	14,575	43,731	40,134
General and administrative	30,363	30,882	98,492	87,807
Operating income	119,117	104,914	301,691	256,906
Interest (expense) income, net	(5,766)	(4,753)	(17,690)	(15,812)
Other (expense) income, net	(399)	77	(310)	438
Intercompany income (expense)	2,717	4,980	8,372	10,974
Income before income taxes	115,669	105,218	292,063	252,506
Income taxes	37,691	39,262	1,065	95,402
Net income	77,978	65,956	290,998	157,104
Depreciation and amortization	10,904	10,048	35,957	28,383
Capital expenditures, including acquisitions	40,872	49,866	128,934	126,184
Total assets	1,372,425		1,372,425		1,249,755
Goodwill	180,063		180,063		179,906
Operating Segments | International | International
Segment Reporting Information [Line Items]
Total service revenues and vehicle sales	66,742	68,036	190,292	187,854
Yard operations	23,941	23,016	68,085	65,640
Cost of vehicle sales	19,776	23,169	57,827	63,805
General and administrative	5,354	4,817	15,579	15,036
Operating income	17,671	17,034	48,801	43,373
Interest (expense) income, net	260	(666)	802	(88)
Other (expense) income, net	205	(38)	427	5,063
Intercompany income (expense)	(2,717)	(4,980)	(8,372)	(10,974)
Income before income taxes	15,419	11,350	41,658	37,374
Income taxes	2,851	2,682	8,764	8,240
Net income	12,568	8,668	32,894	29,134
Depreciation and amortization	2,304	2,310	7,175	7,187
Capital expenditures, including acquisitions	1,426	$ 16,204	5,776	$ 17,649
Total assets	439,261		439,261		400,065
Goodwill	$ 78,571		$ 78,571		$ 80,292