XML 69 R60.htm IDEA: XBRL DOCUMENT
v3.24.1

Earnings Per Share - Additional Information (Detail) | Feb. 29, 2024 | Aug. 31, 2023 | Feb. 28, 2023
--- | --- | --- | ---
2.875% Convertible senior notes, due 2024 |  |  |
Earnings Per Share Disclosure [Line Items] |  |  |
Debt instrument, interest rate | 2.875% | 2.875% | 2.875%
2.875% Convertible senior notes, due 2028 |  |  |
Earnings Per Share Disclosure [Line Items] |  |  |
Debt instrument, interest rate | 2.875% | 2.875% | 2.875%

X
- Definition Earnings Per Share Disclosure [Line Items] + References No definition available. + Details
Name: | gbx_EarningsPerShareDisclosureLineItems
Namespace Prefix: | gbx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=gbx_TwoPointEightSevenFiveConvertibleSeniorNotesDue2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=gbx_TwoPointEightSevenFiveConvertibleSeniorNotesDue2028Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |