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Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail) | 12 Months Ended
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Apr. 30, 2014
Minimum [Member] | Buildings and Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 10 years
Minimum [Member] | Machinery and Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 5 years
Minimum [Member] | Rolling Stock [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 5 years
Minimum [Member] | Containers [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 5 years
Minimum [Member] | Furniture and Fixtures [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 3 years
Maximum [Member] | Buildings and Improvements [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 30 years
Maximum [Member] | Machinery and Equipment [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 10 years
Maximum [Member] | Rolling Stock [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 10 years
Maximum [Member] | Containers [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 12 years
Maximum [Member] | Furniture and Fixtures [Member] |
Property, Plant and Equipment [Line Items] |
Property plant and equipment, estimated useful life | 8 years

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- Details
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- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration