Consolidated Statements of Equity - Entity [Domain] - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total Attributable to Greenbrier	Attributable to Noncontrolling Interest
Beginning balance (in shares) at Aug. 31, 2013		28,084
Beginning balance at Aug. 31, 2013	$ 456,827		$ 259,864	$ 174,842	$ (6,504)	$ 428,202	$ 28,625
Net earnings	89,646			64,563		64,563	25,083
Other comprehensive income (loss), net	4,174				4,120	4,120	54
Noncontrolling interest adjustments	2,953						2,953
Investment by joint venture partner	419						419
Joint venture partner distribution declared	(5,077)						(5,077)
Restricted stock awards (net of cancellations and expense) (in shares)		46
Restricted stock awards (net of cancellations and expense)	11,599		11,599			11,599
Unamortized restricted stock	(12,610)		(12,610)			(12,610)
Restricted stock amortization	6,455		6,455			6,455
Excess tax benefit from restricted stock awards	109		109			109
Repurchase of stock	(26,293)		(26,293)			(26,293)
Repurchase of stock, shares		(641)
Ending Balance (in shares) at May. 31, 2014		27,489
Ending Balance at May. 31, 2014	$ 528,202		239,124	239,405	(2,384)	476,145	52,057
Beginning balance (in shares) at Aug. 31, 2014	27,364	27,364
Beginning balance at Aug. 31, 2014	$ 573,721		235,763	282,559	(6,932)	511,390	62,331
Net earnings	167,353			125,948		125,948	41,405
Other comprehensive income (loss), net	(10,481)				(10,329)	(10,329)	(152)
Noncontrolling interest adjustments	20,371						20,371
Purchase of noncontrolling interest	(80)						(80)
Joint venture partner distribution declared	(13,267)						(13,267)
Restricted stock awards (net of cancellations and expense) (in shares)		(19)
Restricted stock awards (net of cancellations and expense)	22,600		22,600			22,600
Unamortized restricted stock	(24,394)		(24,394)			(24,394)
Restricted stock amortization	13,176		13,176			13,176
Excess tax benefit from restricted stock awards	2,964		2,964			2,964
Conversion of convertible notes, net of debt issuance costs (in shares)		2,471
Conversion of convertible notes, net of debt issuance costs	91,749		91,749			91,749
Cash dividends	(12,257)			(12,257)		(12,257)
Repurchase of stock	$ (48,451)		(48,451)			(48,451)
Repurchase of stock, shares		(891)
Ending Balance (in shares) at May. 31, 2015	28,925	28,925
Ending Balance at May. 31, 2015	$ 783,004		$ 293,407	$ 396,250	$ (17,261)	$ 672,396	$ 110,608