Business Segment Information - Sales and Gross Profit (Details) $ in Millions	3 Months Ended
Aug. 31, 2022 USD ($) segment	Aug. 31, 2021 USD ($)
Disaggregation of revenue by major customer markets
Operating segments (in segments) \| segment	2
Net sales	$ 446.3	$ 455.1
Gross profit	81.9	64.6
Aviation Services
Disaggregation of revenue by major customer markets
Net sales	424.0	435.6
Gross profit	78.0	60.9
Expeditionary Services
Disaggregation of revenue by major customer markets
Net sales	22.3	19.5
Gross profit	$ 3.9	$ 3.7

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

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- Definition

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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