Organization, consolidation and presentation of financial statements.

No definition available.

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- Definition

Share Repurchase Program, Current Authorization Of Shares Purchased

+ References

No definition available.

+ Details

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- Definition

Share Repurchase Program, Current Authorization Of Shares Purchased Amount

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

+ Details

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- Definition

Expiration date for purchase of share under share repurchase plan, in YYYY-MM-DD format. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

+ Details

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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- Definition

Amount remaining authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

No definition available.

+ Details

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Balance Type:	credit
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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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-Topic 946
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-Name Accounting Standards Codification
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-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

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Interim Financial Statements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	May 31, 2026	May 31, 2025	May 31, 2026	May 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Authorized amount under stock repurchase program	$ 100,000,000		$ 100,000,000
Remaining authorized repurchase amount	$ 64,500,000		$ 64,500,000
Number of shares repurchased	0
Share repurchase program, current authorization of shares purchased		507,000	313,000
Share repurchase program, current authorization of shares purchased amount			$ 13,300,000	$ 21,800,000
Repurchase program expiration date			Jan. 31, 2027
Greenbrier-Astra Rail B.V.
Organization, Consolidation and Presentation of Financial Statements [Line Items]
Ownership percentage by parent	75.00%		75.00%