Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock Shares	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect Adjustment Due to Adoption	Accumulated Other Comprehensive (Loss)	Total Equity - Greenbrier	Total Equity - Greenbrier Cumulative Effect Adjustment Due to Adoption	Noncontrolling Interest	Equity Excluding Contingently Redeemable Noncontrolling Interest	Equity Excluding Contingently Redeemable Noncontrolling Interest Cumulative Effect Adjustment Due to Adoption	Contingently Redeemable Noncontrolling Interest
Beginning balance at Aug. 31, 2019			$ 453,943	$ 867,602	$ 4,393	$ (44,815)	$ 1,276,730	$ 4,393	$ 164,967	$ 1,441,697	$ 4,393
Beginning balance (in shares) at Aug. 31, 2019		32,488
Beginning balance at Aug. 31, 2019												$ 31,564
Accounting Standards Update [Extensible List]				us-gaap:AccountingStandardsUpdate201602Member			us-gaap:AccountingStandardsUpdate201602Member			us-gaap:AccountingStandardsUpdate201602Member
Net earnings (loss)	$ 44,026			$ 21,298			$ 21,298		23,510	$ 44,808
Other comprehensive income (loss), net	(3,514)					(3,506)	(3,506)		(8)	(3,514)
Noncontrolling interest adjustments									9,038	9,038
Joint venture partner distribution declared									(8,172)	(8,172)
Noncontrolling interest acquired									12,075	12,075
Restricted stock awards (net of cancellations)			11,114				11,114			11,114
Restricted stock awards (net of cancellations) (in shares)		154
Unamortized restricted stock			(13,008)				(13,008)			(13,008)
Restricted stock amortization			6,859				6,859			6,859
Cash dividends				(17,408)			(17,408)			(17,408)
Ending balance at Feb. 29, 2020			458,908	875,885		(48,321)	1,286,472		201,410	1,487,882
Ending Balance (in shares) at Feb. 29, 2020		32,642
Ending Balance at Feb. 29, 2020												30,782
Net earnings (loss)												(782)
Beginning balance at Nov. 30, 2019			454,900	871,300		(44,392)	1,281,808		191,050	1,472,858
Beginning balance (in shares) at Nov. 30, 2019		32,596
Beginning balance at Nov. 30, 2019												31,723
Net earnings (loss)	20,015			13,629			13,629		7,327	20,956
Other comprehensive income (loss), net	(3,931)					(3,929)	(3,929)		(2)	(3,931)
Noncontrolling interest adjustments									7,302	7,302
Joint venture partner distribution declared									(4,267)	(4,267)
Restricted stock awards (net of cancellations)			1,642				1,642			1,642
Restricted stock awards (net of cancellations) (in shares)		46
Unamortized restricted stock			(1,667)				(1,667)			(1,667)
Restricted stock amortization			4,033				4,033			4,033
Cash dividends				(9,044)			(9,044)			(9,044)
Ending balance at Feb. 29, 2020			458,908	875,885		(48,321)	1,286,472		201,410	1,487,882
Ending Balance (in shares) at Feb. 29, 2020		32,642
Ending Balance at Feb. 29, 2020												30,782
Net earnings (loss)												(941)
Beginning balance at Aug. 31, 2020	$ 1,473,055		460,400	$ 885,460	$ (509)	(52,817)	$ 1,293,043	$ (509)	180,012	$ 1,473,055	$ (509)
Beginning balance (in shares) at Aug. 31, 2020	32,701	32,701
Beginning balance at Aug. 31, 2020												31,117
Accounting Standards Update [Extensible List]				ASU 2016-13			ASU 2016-13			ASU 2016-13
Net earnings (loss)	$ (20,550)			$ (19,037)			$ (19,037)		(433)	$ (19,470)		(1,080)
Other comprehensive income (loss), net	6,137					6,133	6,133		4	6,137
Noncontrolling interest adjustments									(1,285)	(1,285)
Joint venture partner distribution declared									(2,441)	(2,441)
Restricted stock awards (net of cancellations)			15,497				15,497			15,497
Restricted stock awards (net of cancellations) (in shares)		124
Unamortized restricted stock			(17,854)				(17,854)			(17,854)
Restricted stock amortization			8,951				8,951			8,951
Cash dividends				(17,722)			(17,722)			(17,722)
Ending balance at Feb. 28, 2021	$ 1,444,359		466,994	848,192		(46,684)	1,268,502		175,857	1,444,359
Ending Balance (in shares) at Feb. 28, 2021	32,825	32,825
Ending Balance at Feb. 28, 2021												30,037
Beginning balance at Nov. 30, 2020			462,498	866,367		(48,458)	1,280,407		180,455	1,460,862
Beginning balance (in shares) at Nov. 30, 2020		32,824
Beginning balance at Nov. 30, 2020												30,711
Net earnings (loss)	$ (13,921)			(9,065)			(9,065)		(4,182)	(13,247)		(674)
Other comprehensive income (loss), net	1,781					1,774	1,774		7	1,781
Noncontrolling interest adjustments									(14)	(14)
Joint venture partner distribution declared									(409)	(409)
Restricted stock awards (net of cancellations)			1,301				1,301			1,301
Restricted stock awards (net of cancellations) (in shares)		1
Unamortized restricted stock			(1,321)				(1,321)			(1,321)
Restricted stock amortization			4,516				4,516			4,516
Cash dividends				(9,110)			(9,110)			(9,110)
Ending balance at Feb. 28, 2021	$ 1,444,359		$ 466,994	$ 848,192		$ (46,684)	$ 1,268,502		$ 175,857	$ 1,444,359
Ending Balance (in shares) at Feb. 28, 2021	32,825	32,825
Ending Balance at Feb. 28, 2021												$ 30,037