Notes Payable, Net - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	12 Months Ended
	Aug. 31, 2023	Aug. 31, 2022	Jul. 29, 2022	Feb. 09, 2022	Aug. 31, 2021
Debt Instrument [Line Items]
Debt instrument amount outstanding	$ 1,329,900,000	$ 1,290,200,000
ASU 2020-06
Debt Instrument [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Sep. 01, 2021
Other Term Loan Due November 2023 to March 2027
Debt Instrument [Line Items]
Unsecured debt	$ 1,800,000
2026 Term Loan
Debt Instrument [Line Items]
Nonrecourse senior term debt	$ 291,900,000
Debt instrument, maturity month and year	2026-08
Periodic Principal Payment	$ 3,700,000
Balloon payment	$ 222,600,000
Swap agreement interest rate	75.00%
Debt instrument amount outstanding	$ 266,400,000
2026 Term Loan | SOFR
Debt Instrument [Line Items]
Debt instrument, percentage points added to the reference rate	1.50%
2026 Term Loan | SOFR Adjustment
Debt Instrument [Line Items]
Debt instrument, percentage points added to the reference rate	0.10%
2027 Term Loan
Debt Instrument [Line Items]
Nonrecourse senior term debt	$ 343,000,000
Debt instrument, maturity month and year	2027-08
Additional term loan			$ 75,000,000
Additional debt drawn			$ 75,000,000
Periodic Principal Payment	$ 3,100,000
Balloon payment	$ 283,700,000
Swap agreement interest rate	100.00%
Debt instrument amount outstanding	$ 332,700,000
2027 Term Loan | SOFR
Debt Instrument [Line Items]
Debt instrument, percentage points added to the reference rate	1.625%
2027 Term Loan | SOFR Adjustment
Debt Instrument [Line Items]
Debt instrument, percentage points added to the reference rate	0.10%
2.875% Convertible senior notes, due 2028
Debt Instrument [Line Items]
Debt instrument, effective interest rate	5.75%
Debt instrument, interest rate	2.875%	2.875%			2.875%
Description of long term debt	Convertible senior notes, due 2028 (2028 Convertible Notes), bear interest at a fixed rate of 2.875%, paid semiannually in arrears on April 15th and October 15th.
Frequency of payments	semiannually
Debt instrument, maturity date	Apr. 15, 2028
Convertible notes initial conversion rate, shares per $1,000 principal amount	0.180317
Debt instrument, convertible, principal amount	$ 1,000
Convertible notes conversion rate, per share	$ 55.46
Number of shares reserved for future issuance	8.8
2.875% Convertible senior notes, due 2028 | Redemption on or After April 15, 2025
Debt Instrument [Line Items]
Debt instrument, convertible, latest date	Jan. 15, 2028
Debt instrument redemption start date	Apr. 15, 2025
Debt instrument redemption end date	Apr. 15, 2028
Debt instrument, convertible, threshold percentage of stock price trigger	130.00%
Debt instrument redemption description	Additionally, the Company may elect to call the notes on or after April 15, 2025 and on or before the 40th trading day prior to April 15, 2028, at a cash redemption price described in the 2028 Notes Indenture if the stock price exceeds 130% of the conversion price during certain trading days as defined in the 2028 Notes Indenture.
2.875% Convertible senior notes, due 2024
Debt Instrument [Line Items]
Debt instrument, effective interest rate	4.99%
Debt instrument, interest rate	2.875%	2.875%			2.875%
Description of long term debt	Convertible senior notes, due 2024 (2024 Convertible Notes), bear interest at a fixed rate of 2.875%, paid semi-annually in arrears on February 1st and August 1st.
Frequency of payments	semi-annually
Debt instrument, maturity date	Feb. 01, 2024
Convertible notes initial conversion rate, shares per $1,000 principal amount	0.166234
Debt instrument, convertible, principal amount	$ 1,000
Convertible notes conversion rate, per share	$ 60.16
Number of shares reserved for future issuance	1.1
GBX Leasing Warehouse Facility
Debt Instrument [Line Items]
Nonrecourse senior term debt	$ 323,300,000			$ 323,300,000
Debt instrument amount outstanding	$ 307,500,000
GBX Leasing Warehouse Facility | SOFR Adjustment
Debt Instrument [Line Items]
Debt instrument, percentage points added to the reference rate	0.11%