Condensed Consolidating Statement of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Cash flows from operating activities:
Net earnings (loss)	$ 61,170	$ 8,387	$ 8,331
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities:
Deferred income taxes	11,617	2,399	15,052
Depreciation and amortization	42,371	38,293	37,511
Gain on sales of leased equipment	(8,964)	(5,121)	(6,543)
Accretion of debt discount	3,259	6,583	8,149
Special items			(11,870)
Gain on extinguishment of debt (non-cash portion)		8,453	(2,070)
Other	13,662	6,762	4,237
Decrease (increase) in assets:
Accounts receivable	37,763	(96,552)	22,430
Inventories	3,709	(116,866)	(45,212)
Leased railcars for syndication	(76,071)	(20,839)	759
Other		8,863	6,455
Increase (decrease) in liabilities:
Accounts payable and accrued liabilities	16,236	130,673	12,777
Deferred revenue	11,304	(5,287)	(7,445)
Net cash provided by (used in) operating activities	116,056	(34,252)	42,561
Cash flows from investing activities:
Proceeds from sales of equipment	33,560	18,730	22,978
Investment in and net advances to unconsolidated affiliates	(506)	(2,330)	(927)
Contract placement fee			(6,050)
Decrease (increase) in restricted cash	(4,164)	412	(1,442)
Capital expenditures	(117,885)	(84,302)	(38,989)
Other	48	(1,774)	260
Net cash provided by (used in) investing Activities	(88,947)	(69,264)	(24,170)
Cash flows from financing activities:
Net changes in revolving notes with maturities of 90 days or less	(57,302)	71,625	(11,934)
Proceeds from revolving notes with maturities longer than 90 days	63,773	25,159	5,698
Repayment of revolving notes with maturities longer than 90 days	(33,934)	(10,000)	(5,698)
Proceeds from issuance of notes payable	2,750	231,250	2,149
Debt issuance costs		(11,469)	(109)
Repayments of notes payable	(7,070)	(311,360)	(38,267)
Proceeds from equity offering		63,180	56,250
Excess tax benefit from restricted stock awards	1,627
Expenses from equity offering		(420)	(3,542)
Investment by joint venture partner	1,362
Other		26	29
Net cash provided by (used in) financing activities	(28,794)	57,991	4,576
Effect of exchange rate changes	5,034	(3,117)	(290)
Increase (decrease) in cash and cash equivalents	3,349	(48,642)	22,677
Beginning of period	50,222	98,864	76,187
End of period	53,571	50,222	98,864
Parent
Cash flows from operating activities:
Net earnings (loss)	58,708	6,466	4,277
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities:
Deferred income taxes	23,749	(15,380)	5,898
Depreciation and amortization	2,596	2,701	2,063
Accretion of debt discount	3,259	6,583	8,149
Special items			(11,870)
Gain on extinguishment of debt (non-cash portion)		8,453	(2,070)
Other	8,757	7,073	5,175
Decrease (increase) in assets:
Accounts receivable	13,197	3,033	(9,292)
Other	1,847	4,265	648
Increase (decrease) in liabilities:
Accounts payable and accrued liabilities	(43,798)	394	3,143
Deferred revenue	(155)	(155)	(155)
Net cash provided by (used in) operating activities	68,160	23,433	5,966
Cash flows from investing activities:
Investment in and net advances to unconsolidated affiliates	(103,703)	(57,373)	(36,697)
Intercompany advances	19,092	(1,334)	7,866
Capital expenditures	(709)	(1,996)	(3,645)
Net cash provided by (used in) investing Activities	(85,320)	(60,703)	(32,476)
Cash flows from financing activities:
Net changes in revolving notes with maturities of 90 days or less	(60,000)	60,000
Intercompany advances	76,476	(55,401)	33,850
Proceeds from issuance of notes payable		230,000
Debt issuance costs		(11,469)
Repayments of notes payable		(306,750)	(32,090)
Proceeds from equity offering		63,180	56,250
Excess tax benefit from restricted stock awards	1,627
Expenses from equity offering		(420)	(3,542)
Other		26	29
Net cash provided by (used in) financing activities	18,103	(20,834)	54,497
Effect of exchange rate changes	12
Increase (decrease) in cash and cash equivalents	955	(58,104)	27,987
Beginning of period	33,368	91,472	63,485
End of period	34,323	33,368	91,472
Combined Guarantor Subsidiaries
Cash flows from operating activities:
Net earnings (loss)	84,670	51,275	30,110
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities:
Deferred income taxes	(7,548)	16,560	10,045
Depreciation and amortization	31,618	29,413	28,241
Gain on sales of leased equipment	(8,963)	(4,979)	(6,543)
Other	1,024	151	354
Decrease (increase) in assets:
Accounts receivable	44,373	(97,572)	17,743
Inventories	3,395	(3,503)	(19,135)
Leased railcars for syndication	(78,863)	(21,857)	1,778
Other	(393)	3,181	6,773
Increase (decrease) in liabilities:
Accounts payable and accrued liabilities	55,609	36,161	(9,134)
Deferred revenue	10,711	(4,154)	(8,353)
Net cash provided by (used in) operating activities	135,633	4,676	51,879
Cash flows from investing activities:
Proceeds from sales of equipment	33,560	18,730	22,978
Investment in and net advances to unconsolidated affiliates	230	(8,420)	3,650
Contract placement fee			(6,050)
Decrease (increase) in restricted cash	66	412	(1,442)
Capital expenditures	(89,531)	(65,140)	(30,430)
Other	48	61	260
Net cash provided by (used in) investing Activities	(55,627)	(54,357)	(11,034)
Cash flows from financing activities:
Intercompany advances	(76,936)	52,806	(34,061)
Proceeds from issuance of notes payable	250		328
Repayments of notes payable	(4,166)	(4,206)	(5,772)
Net cash provided by (used in) financing activities	(80,852)	48,600	(39,505)
Effect of exchange rate changes	611	751	(902)
Increase (decrease) in cash and cash equivalents	(235)	(330)	438
Beginning of period	529	859	421
End of period	294	529	859
Combined Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net earnings (loss)	20,979	15,193	7,101
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities:
Deferred income taxes	(2,520)	1,311	427
Depreciation and amortization	8,236	6,250	7,280
Other	37	(465)	(1,972)
Decrease (increase) in assets:
Accounts receivable	(20,223)	(1,992)	12,914
Inventories	313	(113,667)	(26,077)
Leased railcars for syndication		1,018	(1,019)
Other	4,878	338	(966)
Increase (decrease) in liabilities:
Accounts payable and accrued liabilities	4,448	94,096	18,765
Deferred revenue	735	(978)	1,063
Net cash provided by (used in) operating activities	16,883	1,104	17,516
Cash flows from investing activities:
Investment in and net advances to unconsolidated affiliates	(614)
Decrease (increase) in restricted cash	(4,230)
Capital expenditures	(28,684)	(17,168)	(5,594)
Other		(1,835)
Net cash provided by (used in) investing Activities	(33,528)	(19,003)	(5,594)
Cash flows from financing activities:
Net changes in revolving notes with maturities of 90 days or less	2,698	11,625	(11,934)
Proceeds from revolving notes with maturities longer than 90 days	63,773	25,159	5,698
Repayment of revolving notes with maturities longer than 90 days	(33,934)	(10,000)	(5,698)
Intercompany advances	(18,632)	3,929	(7,655)
Proceeds from issuance of notes payable	2,500	1,250	1,821
Debt issuance costs			(109)
Repayments of notes payable	(2,904)	(404)	(405)
Investment by joint venture partner	1,362
Net cash provided by (used in) financing activities	14,863	31,559	(18,282)
Effect of exchange rate changes	4,411	(3,868)	612
Increase (decrease) in cash and cash equivalents	2,629	9,792	(5,748)
Beginning of period	16,325	6,533	12,281
End of period	18,954	16,325	6,533
Eliminations
Cash flows from operating activities:
Net earnings (loss)	(103,187)	(64,547)	(33,157)
Adjustments to reconcile net earnings (loss) to net cash provided by (used in) operating activities:
Deferred income taxes	(2,064)	(92)	(1,318)
Depreciation and amortization	(79)	(71)	(73)
Gain on sales of leased equipment	(1)	(142)
Other	3,844	3	680
Decrease (increase) in assets:
Accounts receivable	416	(21)	1,065
Inventories	1	304
Leased railcars for syndication	2,792
Other	(6,332)	1,079
Increase (decrease) in liabilities:
Accounts payable and accrued liabilities	(23)	22	3
Deferred revenue	13
Net cash provided by (used in) operating activities	(104,620)	(63,465)	(32,800)
Cash flows from investing activities:
Investment in and net advances to unconsolidated affiliates	103,581	63,463	32,120
Intercompany advances	(19,092)	1,334	(7,866)
Capital expenditures	1,039	2	680
Net cash provided by (used in) investing Activities	85,528	64,799	24,934
Cash flows from financing activities:
Intercompany advances	19,092	(1,334)	7,866
Net cash provided by (used in) financing activities	$ 19,092	$ (1,334)	$ 7,866