Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Nov. 30, 2018	Jun. 30, 2017
Related Party Transaction [Line Items]
Carrying amount of investment in unconsolidated affiliates	$ 5.5
Percentage of recognized revenue and margin from sale	60.00%
Percentage of deferred revenue and margin from sale	40.00%
Revenue recognize from railcars sold	$ 4.0
Leasing Warehouse
Related Party Transaction [Line Items]
Revenue recognize from railcars sold	0.0
Greenbrier
Related Party Transaction [Line Items]
Percentage of ownership in entity		40.00%
Amsted-Maxion Cruzeiro
Related Party Transaction [Line Items]
Note receivable	10.0
Greenbrier-Maxion
Related Party Transaction [Line Items]
Note receivable	$ 19.5

Amount recognized from sale of railcars accounted for under equity method accounting.

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- Definition

Percentage of deferred revenue and margin from sale.

+ References

No definition available.

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Percentage of recognized revenue and margin from sale.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
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- Definition

Amount of investment in equity method investee and investment in and advance to affiliate.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 220
-Section S99
-Paragraph 1
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