Condensed Consolidating Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Revenue
Revenue	$ 714,606	$ 593,285	$ 1,839,813	$ 1,585,856
Cost of revenue
Cost of revenue	565,320	496,510	1,477,149	1,369,671
Margin	149,286	96,775	362,664	216,185
Selling and administrative expense	45,595	34,800	112,223	89,034
Net (gain) loss on disposition of equipment	(720)	(5,619)	(924)	(14,686)
Restructuring charges		56		1,475
Earnings (loss) from operations	104,411	67,538	251,365	140,362
Other costs
Interest and foreign exchange	4,285	5,437	9,355	14,280
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	100,126	62,101	242,010	126,082
Income tax (expense) benefit	(30,783)	(16,303)	(76,209)	(36,708)
Earnings (loss) before earnings (loss) from unconsolidated affiliates	69,343	45,798	165,801	89,374
Earnings (loss) from unconsolidated affiliates	982	298	1,552	272
Net earnings (loss)	70,325	46,096	167,353	89,646
Net (earnings) loss attributable to noncontrolling interest	(27,514)	(12,508)	(41,405)	(25,083)
Net earnings (loss) attributable to Greenbrier	42,811	33,588	125,948	64,563
Manufacturing
Revenue
Revenue	593,376	425,583	1,478,566	1,132,811
Cost of revenue
Cost of revenue	465,658	351,829	1,184,922	969,841
Wheels, Repairs & Parts
Revenue
Revenue		140,663		390,604
Cost of revenue
Cost of revenue		129,825		365,740
Leasing & Services
Revenue
Revenue	23,823	27,039	74,576	62,441
Cost of revenue
Cost of revenue	10,017	14,856	32,942	34,090
Wheels & Parts
Revenue
Revenue	97,407	140,663	286,671	390,604
Cost of revenue
Cost of revenue	89,645	129,825	259,285	365,740
Parent
Revenue
Revenue	(90)	108	83	865
Cost of revenue
Margin	(90)	108	83	865
Selling and administrative expense	24,851	13,987	55,116	31,698
Earnings (loss) from operations	(24,941)	(13,879)	(55,033)	(30,833)
Other costs
Interest and foreign exchange	3,240	2,918	9,345	8,751
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	(28,181)	(16,797)	(64,378)	(39,584)
Income tax (expense) benefit	4,215	3,337	(4,476)	10,772
Earnings (loss) before earnings (loss) from unconsolidated affiliates	(23,966)	(13,460)	(68,854)	(28,812)
Earnings (loss) from unconsolidated affiliates	66,777	47,048	194,802	93,375
Net earnings (loss)	42,811	33,588	125,948	64,563
Net earnings (loss) attributable to Greenbrier	42,811	33,588	125,948	64,563
Parent | Leasing & Services
Revenue
Revenue	(90)	108	83	865
Combined Guarantor Subsidiaries
Revenue
Revenue	403,436	381,317	1,242,386	1,073,758
Cost of revenue
Cost of revenue	331,315	331,515	1,032,183	957,649
Margin	72,121	49,802	210,203	116,109
Selling and administrative expense	10,688	10,645	26,905	29,802
Net (gain) loss on disposition of equipment	(724)	(5,411)	(927)	(13,556)
Restructuring charges		56		1,475
Earnings (loss) from operations	62,157	44,512	184,225	98,388
Other costs
Interest and foreign exchange	1,649	1,417	4,998	3,180
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	60,508	43,095	179,227	95,208
Income tax (expense) benefit	(26,025)	(11,506)	(62,438)	(31,059)
Earnings (loss) before earnings (loss) from unconsolidated affiliates	34,483	31,589	116,789	64,149
Earnings (loss) from unconsolidated affiliates	5,142	5,412	21,377	7,857
Net earnings (loss)	39,625	37,001	138,166	72,006
Net earnings (loss) attributable to Greenbrier	39,625	37,001	138,166	72,006
Combined Guarantor Subsidiaries | Manufacturing
Revenue
Revenue	280,928	211,921	877,405	617,120
Cost of revenue
Cost of revenue	230,143	184,870	735,414	552,871
Combined Guarantor Subsidiaries | Wheels, Repairs & Parts
Revenue
Revenue		142,625		395,537
Cost of revenue
Cost of revenue		131,769		370,626
Combined Guarantor Subsidiaries | Leasing & Services
Revenue
Revenue	23,762	26,771	74,064	61,101
Cost of revenue
Cost of revenue	10,041	14,876	33,014	34,152
Combined Guarantor Subsidiaries | Wheels & Parts
Revenue
Revenue	98,746		290,917
Cost of revenue
Cost of revenue	91,131		263,755
Combined Non-Guarantor Subsidiaries
Revenue
Revenue	492,302	363,401	1,285,604	981,041
Cost of revenue
Cost of revenue	418,273	315,398	1,091,498	876,395
Margin	74,029	48,003	194,106	104,646
Selling and administrative expense	9,912	10,016	30,169	27,083
Net (gain) loss on disposition of equipment	7	(205)	7	(820)
Earnings (loss) from operations	64,110	38,192	163,930	78,383
Other costs
Interest and foreign exchange	(604)	1,102	(4,988)	2,349
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	64,714	37,090	168,918	76,034
Income tax (expense) benefit	(7,888)	(8,388)	(22,559)	(18,044)
Earnings (loss) before earnings (loss) from unconsolidated affiliates	56,826	28,702	146,359	57,990
Earnings (loss) from unconsolidated affiliates	47	44	142	121
Net earnings (loss)	56,873	28,746	146,501	58,111
Net (earnings) loss attributable to noncontrolling interest	(26,415)	(12,830)	(61,992)	(27,362)
Net earnings (loss) attributable to Greenbrier	30,458	15,916	84,509	30,749
Combined Non-Guarantor Subsidiaries | Manufacturing
Revenue
Revenue	492,302	363,401	1,285,603	981,040
Cost of revenue
Cost of revenue	418,273	315,398	1,091,498	876,395
Combined Non-Guarantor Subsidiaries | Leasing & Services
Revenue
Revenue			1	1
Eliminations
Revenue
Revenue	(181,042)	(151,541)	(688,260)	(469,808)
Cost of revenue
Cost of revenue	(184,268)	(150,403)	(646,532)	(464,373)
Margin	3,226	(1,138)	(41,728)	(5,435)
Selling and administrative expense	144	152	33	451
Net (gain) loss on disposition of equipment	(3)	(3)	(4)	(310)
Earnings (loss) from operations	3,085	(1,287)	(41,757)	(5,576)
Other costs
Earnings (loss) before income taxes and earnings (loss) from unconsolidated affiliates	3,085	(1,287)	(41,757)	(5,576)
Income tax (expense) benefit	(1,085)	254	13,264	1,623
Earnings (loss) before earnings (loss) from unconsolidated affiliates	2,000	(1,033)	(28,493)	(3,953)
Earnings (loss) from unconsolidated affiliates	(70,984)	(52,206)	(214,769)	(101,081)
Net earnings (loss)	(68,984)	(53,239)	(243,262)	(105,034)
Net (earnings) loss attributable to noncontrolling interest	(1,099)	322	20,587	2,279
Net earnings (loss) attributable to Greenbrier	(70,083)	(52,917)	(222,675)	(102,755)
Eliminations | Manufacturing
Revenue
Revenue	(179,854)	(149,739)	(684,442)	(465,349)
Cost of revenue
Cost of revenue	(182,758)	(148,439)	(641,990)	(459,425)
Eliminations | Wheels, Repairs & Parts
Revenue
Revenue		(1,962)		(4,933)
Cost of revenue
Cost of revenue		(1,944)		(4,886)
Eliminations | Leasing & Services
Revenue
Revenue	151	160	428	474
Cost of revenue
Cost of revenue	(24)	$ (20)	(72)	$ (62)
Eliminations | Wheels & Parts
Revenue
Revenue	(1,339)		(4,246)
Cost of revenue
Cost of revenue	$ (1,486)		$ (4,470)