Consolidated Statements of Cash Flows - Entity [Domain] - USD ($) $ in Thousands	9 Months Ended
	May. 31, 2015	May. 31, 2014
Cash flows from operating activities
Net earnings	$ 167,353	$ 89,646
Adjustments to reconcile net earnings to net cash provided by operating activities:
Deferred income taxes	(5,245)	(6,745)
Depreciation and amortization	33,258	30,824
Net gain on disposition of equipment	(924)	(14,686)
Stock based compensation expense	13,176	6,454
Noncontrolling interest adjustments	20,371	2,953
Other	1,008	388
Increase in assets:
Accounts receivable, net	(8,769)	(26,226)
Inventories	(124,906)	(21,722)
Leased railcars for syndication	(90,914)	(25,420)
Other	(1,666)	(2,491)
Increase in liabilities:
Accounts payable and accrued liabilities	23,135	36,507
Deferred revenue	3,680	12,258
Net cash provided by operating activities	29,557	81,740
Cash flows from investing activities
Proceeds from sales of assets	4,628	39,515
Capital expenditures	(75,892)	(34,522)
Decrease (increase) in restricted cash	228	(661)
Investment in and advances to unconsolidated affiliates	(29,923)	(1,253)
Other	715
Net cash provided by (used in) investing activities	(100,244)	3,079
Cash flows from financing activities
Net change in revolving notes with maturities of 90 days or less	73,000
Proceeds from revolving notes with maturities longer than 90 days	42,563	34,674
Repayments of revolving notes with maturities longer than 90 days	(36,137)	(64,801)
Proceeds from issuance of notes payable		200,000
Repayments of notes payable	(5,504)	(126,821)
Debt issuance costs		(382)
Repurchase of stock	(48,451)	(26,293)
Dividends	(12,069)
Decrease in restricted cash	11,000
Cash distribution to joint venture partner	(12,489)	(3,109)
Investment by joint venture partner		419
Excess tax benefit from restricted stock awards	2,964	109
Other	(248)
Net cash provided by (used in) financing activities	14,629	13,796
Effect of exchange rate changes	(6,075)	2,442
Increase (decrease) in cash and cash equivalents	(62,133)	101,057
Cash and cash equivalents
Beginning of period	184,916	97,435
End of period	122,783	198,492
Cash paid during the period for
Interest	13,509	12,816
Income taxes, net	87,829	41,643
Non-cash activity
Conversion of convertible notes, net of debt issuance costs	91,749
Dividends declared and accrued in Accounts payable and accrued liabilities	188
Transfer from Leased railcars for syndication to Equipment on operating leases, net	3,313
Capital expenditures accrued in Accounts payable and accrued liabilities	$ 2,304
Transfer of Inventories to Leased railcars for syndication		$ 2,691