Schedule of Segment Reporting Information by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Segment Reporting Information [Line Items]
Net sales	$ 1,971,560	$ 1,588,525	$ 4,203,228	$ 3,297,056
Income (loss) before income taxes	141,065	98,365	328,156	214,165
Operating Segments | Recreational vehicles
Segment Reporting Information [Line Items]
Income (loss) before income taxes	154,266	106,488	350,703	229,584
Operating Segments | Recreational vehicles | Towables
Segment Reporting Information [Line Items]
Income (loss) before income taxes	116,728	78,000	275,579	172,173
Operating Segments | Recreational vehicles | Motorized
Segment Reporting Information [Line Items]
Income (loss) before income taxes	37,538	28,488	75,124	57,411
Operating Segments | Other
Segment Reporting Information [Line Items]
Income (loss) before income taxes	5,290	5,696	13,773	12,074
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Income (loss) before income taxes	(18,491)	(13,819)	(36,320)	(27,493)
Continuing Operations
Segment Reporting Information [Line Items]
Net sales	1,971,560	1,588,525	4,203,228	3,297,056
Continuing Operations | Operating Segments | Recreational vehicles
Segment Reporting Information [Line Items]
Net sales	1,933,027	1,557,221	4,118,139	3,229,548
Continuing Operations | Operating Segments | Recreational vehicles | Towables
Segment Reporting Information [Line Items]
Net sales	1,373,118	1,082,249	2,991,619	2,293,122
Continuing Operations | Operating Segments | Recreational vehicles | Motorized
Segment Reporting Information [Line Items]
Net sales	559,909	474,972	1,126,520	936,426
Continuing Operations | Operating Segments | Other
Segment Reporting Information [Line Items]
Net sales	68,013	53,891	150,932	112,887
Continuing Operations | Intercompany Eliminations
Segment Reporting Information [Line Items]
Net sales	$ (29,480)	$ (22,587)	$ (65,843)	$ (45,379)