Business Segment Information (Details) $ in Millions	3 Months Ended
Aug. 31, 2016 USD ($) segment	Aug. 31, 2015 USD ($)
Business Segment Information
Number of business segments \| segment	2
Business Segment Information
Sales	$ 404.8	$ 386.7
Gross Profit	61.5	53.9
Aviation Services
Business Segment Information
Sales	334.6	315.8
Gross Profit	53.4	49.9
Expeditionary Services
Business Segment Information
Sales	70.2	70.9
Gross Profit	$ 8.1	$ 4.0

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1,2)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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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.

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