XML 82 R71.htm IDEA: XBRL DOCUMENT
v3.23.1

Leases - Supplemental Cash Flow Information Related to Leases (Detail) $ in Millions | 6 Months Ended
--- | ---
Feb. 28, 2023 USD ($)
Cash Flow, Operating Activities, Lessee [Abstract] |
Operating cash flows from operating leases | $ 6.7
ROU assets obtained in exchange for new operating lease liabilities | $ 1.1

X
- Definition Right of use asset obtained in exchange for operating lease liabilities. + References No definition available. + Details
Name: | gbx_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiabilities
Namespace Prefix: | gbx_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_CashFlowOperatingActivitiesLesseeAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918643-209977 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980 + Details
Name: | us-gaap_OperatingLeasePayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration