Segments Internal Financial Reports (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	May 31, 2013		May 31, 2012	May 31, 2013		May 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 433,663		$ 507,797	$ 1,272,203		$ 1,364,181
Margin	50,019		61,938	146,073		159,879
Selling and administrative	25,322		28,784	76,364		76,998
Net gain on disposition of equipment	(5,131)		(2,585)	(9,615)		(8,897)
Interest and foreign exchange	5,905		6,560	18,127		18,574
Goodwill impairment	76,900	[1]		76,900	[1],[2]
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	(52,977)		29,179	(15,703)		73,204
Manufacturing
Segment Reporting Information [Line Items]
Revenues	299,750		370,993	845,198		1,004,507
Margin	31,231		39,506	89,504		95,328
Wheels Repair And Parts
Segment Reporting Information [Line Items]
Revenues	133,715		128,925	366,850		375,242
Margin	10,691		13,535	30,133		38,733
Goodwill impairment				76,900	[2]
Leasing and Services
Segment Reporting Information [Line Items]
Revenues	20,758		24,196	62,679		70,585
Margin	8,097		8,897	26,436		25,818
Intersegment Elimination
Segment Reporting Information [Line Items]
Revenues	$ (20,560)		$ (16,317)	$ (2,524)		$ (86,153)

[1] Relates to the Wheels, Repair & Parts segment.

[2] Goodwill impairment relates to the non-cash goodwill impairment charge recognized as part of the Company's annual goodwill impairment analysis as further discussed below.