Condensed Consolidating Statement of Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Condensed Statement of Income Captions [Line Items]
Net earnings (loss)		$ 70,325	$ 46,096	$ 167,353	$ 89,646
Other comprehensive income (loss)
Translation adjustment		(1,299)	80	(10,990)	3,402
Reclassification of derivative financial instruments recognized in net earnings (loss)	[1]	(254)	4	417	321
Unrealized gain (loss) on derivative financial instruments	[2]	107	(659)	(7)	454
Other (net of tax effect)		93	(4)	99	(3)
Other comprehensive income (loss)		(1,353)	(579)	(10,481)	4,174
Comprehensive income (loss)		68,972	45,517	156,872	93,820
Comprehensive (income) loss attributable to noncontrolling interest		(27,497)	(12,501)	(41,253)	(25,137)
Comprehensive income (loss) attributable to Greenbrier		41,475	33,016	115,619	68,683
Parent
Condensed Statement of Income Captions [Line Items]
Net earnings (loss)		42,811	33,588	125,948	64,563
Other comprehensive income (loss)
Comprehensive income (loss)		42,811	33,588	125,948	64,563
Comprehensive income (loss) attributable to Greenbrier		42,811	33,588	125,948	64,563
Combined Guarantor Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net earnings (loss)		39,625	37,001	138,166	72,006
Other comprehensive income (loss)
Translation adjustment		(18)	73	(137)	86
Reclassification of derivative financial instruments recognized in net earnings (loss)		275	276	837	787
Unrealized gain (loss) on derivative financial instruments		(443)	139	(1,640)	1,245
Other comprehensive income (loss)		(186)	488	(940)	2,118
Comprehensive income (loss)		39,439	37,489	137,226	74,124
Comprehensive income (loss) attributable to Greenbrier		39,439	37,489	137,226	74,124
Combined Non-Guarantor Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net earnings (loss)		56,873	28,746	146,501	58,111
Other comprehensive income (loss)
Translation adjustment		(1,281)	7	(10,853)	3,316
Reclassification of derivative financial instruments recognized in net earnings (loss)		(529)	(272)	(420)	(466)
Unrealized gain (loss) on derivative financial instruments		550	(798)	1,633	(791)
Other (net of tax effect)		93	(4)	99	(3)
Other comprehensive income (loss)		(1,167)	(1,067)	(9,541)	2,056
Comprehensive income (loss)		55,706	27,679	136,960	60,167
Comprehensive (income) loss attributable to noncontrolling interest		(26,398)	(12,823)	(61,840)	(27,416)
Comprehensive income (loss) attributable to Greenbrier		29,308	14,856	75,120	32,751
Eliminations
Condensed Statement of Income Captions [Line Items]
Net earnings (loss)		(68,984)	(53,239)	(243,262)	(105,034)
Other comprehensive income (loss)
Comprehensive income (loss)		(68,984)	(53,239)	(243,262)	(105,034)
Comprehensive (income) loss attributable to noncontrolling interest		(1,099)	322	20,587	2,279
Comprehensive income (loss) attributable to Greenbrier		$ (70,083)	$ (52,917)	$ (222,675)	$ (102,755)

[1] Net of tax of effect of $0.04 million and $0.1 million for the three months ended May 31, 2015 and 2014 and $0.4 million and $0.4 million for the nine months ended May 31, 2015 and 2014.

[2] Net of tax of effect of $0.1 million and $0.5 million for the three months ended May 31, 2015 and 2014 and $0.6 million and $0.2 million for the nine months ended May 31, 2015 and 2014.