Condensed Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total Equity - Greenbrier	Noncontrolling Interest	Equity Excluding Contingently Redeemable Noncontrolling Interest	Contingently Redeemable Noncontrolling Interest
Beginning balance at Aug. 31, 2022			$ 424.8	$ 897.7	$ (45.6)	$ 1,276.9	$ 152.2	$ 1,429.1
Beginning balance (in shares) at Aug. 31, 2022		32,600,000
Beginning balance at Aug. 31, 2022									$ 27.7
Net earnings	$ 19.5			16.4		16.4	3.3	19.7	(0.2)
Other comprehensive income (loss), net	23.9				23.9	23.9		23.9
Noncontrolling interest adjustments			(7.9)			(7.9)	(2.0)	(9.9)
Restricted stock awards (net of cancellations) (in shares)		200,000
Unamortized restricted stock			(11.4)			(11.4)		(11.4)
Stock based compensation expense			5.9			5.9		5.9
Restricted stock awards (net of cancellations)			9.0			9.0		9.0
Repurchase of stock	$ (17.4)		(17.4)			(17.4)		(17.4)
Repurchase of stock (in shares)	(575,000)	(500,000)
Joint venture partner distribution declared							(8.9)	(8.9)
Cash dividends				(18.1)		(18.1)		(18.1)
Ending balance at Feb. 28, 2023			403.0	896.0	(21.7)	1,277.3	144.6	1,421.9
Ending Balance (in shares) at Feb. 28, 2023		32,300,000
Ending Balance at Feb. 28, 2023									27.5
Beginning balance at Nov. 30, 2022			425.6	871.9	(31.7)	1,265.8	152.1	1,417.9
Beginning balance (in shares) at Nov. 30, 2022		32,800,000
Beginning balance at Nov. 30, 2022									27.7
Net earnings	$ 36.8			33.1		33.1	3.9	37.0	(0.2)
Other comprehensive income (loss), net	10.0				10.0	10.0		10.0
Noncontrolling interest adjustments			(7.9)			(7.9)	(7.5)	(15.4)
Unamortized restricted stock			(0.5)			(0.5)		(0.5)
Stock based compensation expense			2.7			2.7		2.7
Restricted stock awards (net of cancellations)			0.5			0.5		0.5
Repurchase of stock	$ (17.4)		(17.4)			(17.4)		(17.4)
Repurchase of stock (in shares)	(575,000)	(500,000)
Joint venture partner distribution declared							(3.9)	(3.9)
Cash dividends				(9.0)		(9.0)		(9.0)
Ending balance at Feb. 28, 2023			403.0	896.0	(21.7)	1,277.3	144.6	1,421.9
Ending Balance (in shares) at Feb. 28, 2023		32,300,000
Ending Balance at Feb. 28, 2023									27.5
Beginning balance at Aug. 31, 2023	$ 1,410.2		364.4	897.5	(7.3)	1,254.6	155.6	1,410.2
Beginning balance (in shares) at Aug. 31, 2023	30,880,000	30,900,000
Beginning balance at Aug. 31, 2023									55.6
Net earnings	$ 66.8			64.6		64.6	1.8	66.4	0.4
Other comprehensive income (loss), net	(1.6)				(1.6)	(1.6)		(1.6)
Noncontrolling interest adjustments							1.6	1.6
Restricted stock awards (net of cancellations) (in shares)		200,000
Unamortized restricted stock			(19.2)			(19.2)		(19.2)
Stock based compensation expense			8.1			8.1		8.1
Restricted stock awards (net of cancellations)			14.1			14.1		14.1
Repurchase of stock	$ (1.3)		(1.3)			(1.3)		(1.3)
Repurchase of stock (in shares)	(38,000)
Joint venture partner distribution declared							(4.4)	(4.4)
Cash dividends				(19.4)		(19.4)		(19.4)
Ending balance at Feb. 29, 2024	$ 1,454.5		366.1	942.7	(8.9)	1,299.9	154.6	1,454.5
Ending Balance (in shares) at Feb. 29, 2024	31,131,000	31,100,000
Ending Balance at Feb. 29, 2024									56.0
Beginning balance at Nov. 30, 2023			361.3	919.1	(6.4)	1,274.0	157.1	1,431.1
Beginning balance (in shares) at Nov. 30, 2023		31,100,000
Beginning balance at Nov. 30, 2023									56.5
Net earnings	$ 33.6			33.4		33.4	0.7	34.1	(0.5)
Other comprehensive income (loss), net	$ (2.5)				(2.5)	(2.5)		(2.5)
Noncontrolling interest adjustments							1.2	1.2
Restricted stock awards (net of cancellations) (in shares)		0
Unamortized restricted stock			(3.6)			(3.6)		(3.6)
Stock based compensation expense			4.7			4.7		4.7
Restricted stock awards (net of cancellations)			3.7			3.7		3.7
Repurchase of stock (in shares)	0
Joint venture partner distribution declared							(4.4)	(4.4)
Cash dividends				(9.8)		(9.8)		(9.8)
Ending balance at Feb. 29, 2024	$ 1,454.5		$ 366.1	$ 942.7	$ (8.9)	$ 1,299.9	$ 154.6	$ 1,454.5
Ending Balance (in shares) at Feb. 29, 2024	31,131,000	31,100,000
Ending Balance at Feb. 29, 2024									$ 56.0