Schedule of Segment Reporting Information by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Segment Reporting Information [Line Items]
Net sales	$ 2,251,570	$ 2,015,224	$ 6,454,798	$ 5,312,280
Income (loss) before income taxes	180,525	166,231	508,681	380,396
Operating Segments | Recreational vehicles
Segment Reporting Information [Line Items]
Net sales	2,206,673	1,976,075	6,324,812	5,205,623
Income (loss) before income taxes	186,761	171,860	537,464	401,444
Operating Segments | Recreational vehicles | Towables
Segment Reporting Information [Line Items]
Net sales	1,608,214	1,426,192	4,599,833	3,719,314
Income (loss) before income taxes	147,853	134,504	423,432	306,677
Operating Segments | Recreational vehicles | Motorized
Segment Reporting Information [Line Items]
Net sales	598,459	549,883	1,724,979	1,486,309
Income (loss) before income taxes	38,908	37,356	114,032	94,767
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	82,239	70,019	233,171	182,906
Income (loss) before income taxes	8,872	8,713	22,645	20,787
Intercompany Eliminations
Segment Reporting Information [Line Items]
Net sales	(37,342)	(30,870)	(103,185)	(76,249)
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ (15,108)	$ (14,342)	$ (51,428)	$ (41,835)