Agreement Expiration Time

No definition available.

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- Definition

Cash collateral.

+ References

No definition available.

+ Details

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

Number of Rail Cars Sold

+ References

No definition available.

+ Details

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- Definition

Operating Leased Assets, Gross

+ References

No definition available.

+ Details

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- Definition

Percentage Of Ownership Interests By Third Party.

+ References

No definition available.

+ Details

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- Definition

Value of railcars.

+ References

No definition available.

+ Details

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- Definition

Amount of contractual obligation, including but not limited to, long-term debt, capital lease obligations, operating lease obligations, purchase obligations, and other commitments.

+ References

No definition available.

+ Details

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- Definition

Description of the transaction or nature of business giving rise to deferred revenue or unearned revenue, other than annual membership fees. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 13.A.4(a).Q1)

-URI http://asc.fasb.org/extlink&oid=6600647&loc=d3e214044-122780

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6361293&loc=d3e6935-107765

+ Details

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- Details

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- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph a

-URI http://asc.fasb.org/extlink&oid=7880789&loc=d3e5728-111685

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Balance Type:	debit
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- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7880789&loc=SL6759159-111685

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Variable Interest Entities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended
	Mar. 31, 2012	Nov. 30, 2012 Vehicle	May 31, 2012 Vehicle	Nov. 30, 2012 Maximum	Nov. 30, 2013 Future Period Vehicle	Nov. 30, 2012 Additional Investigation Year Vehicle	Nov. 30, 2012 Intangible and Other Assets	Mar. 31, 2012 Property Subject to Operating Lease Vehicle
Variable Interest Entity [Line Items]
Ownership interest in VIE	1.00%
Third party ownership interest	99.00%
Number of railcars sold		943	743		420	200		1,363
Operating leases	$ 115.4
Target rate of return		8.0
Agreement expiration time		2033-03
Value of railcars		77.0	61.1			15.9
Maximum potential obligation				5.3
Description of deferred revenue		This $5.3 million, which is held in restricted cash, was recorded as a reduction in revenue on the sale of 800 new railcars and a reduction in gain on sale on the sale of the 143 used railcars with a credit to deferred revenue.
Carrying amounts							$ 0.8