Schedule of Changes in Carrying Value of Goodwill (Detail) $ in Thousands	12 Months Ended
	Aug. 31, 2017 USD ($)
Goodwill [Line Items]
Beginning balance	$ 43,265
Addition	25,325	[1]
Ending balance	68,590
Gross goodwill balance before accumulated goodwill impairment losses and other reductions	221,115
Accumulated goodwill impairment losses	(128,209)
Accumulated other reductions	(24,316)
Manufacturing
Goodwill [Line Items]
Addition	25,325	[1]
Ending balance	25,325
Wheels & Parts
Goodwill [Line Items]
Beginning balance	43,265
Ending balance	$ 43,265

[1] Addition to goodwill relates to Greenbrier-Astra Rail transaction. See Note 3 - Acquisitions.