Sale of Receivables (Details) - Purchase Agreement - USD ($) $ in Millions	12 Months Ended
May 31, 2019	May 31, 2018	Feb. 23, 2018
Sale of Receivables
Retained interests	$ 0.0
Sale of Receivables	744.2	$ 239.6
Amount remitted to the Purchaser	729.7	167.9
Amount collected	19.8	10.5
Maximum
Sale of Receivables
Sale of Receivables			$ 150.0
Other expense, net
Sale of Receivables
Discount and other fees	$ 2.2	$ 0.9

The amount of purchase discount and other fees relating to sales receivables.

No definition available.

Name:	air_PurchaseDiscountAndOtherFees
Namespace Prefix:	air_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount remitted to the purchaser in relation to receivables held-for-sale.

+ References

No definition available.

+ Details

Name:	air_ReceivablesHeldForSaleRemittedAmount
Namespace Prefix:	air_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount retained interests in the sold receivables, other than limited recourse obligations in certain circumstances.

+ References

No definition available.

+ Details

Name:	air_RetainedInterestInSoldReceivables
Namespace Prefix:	air_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Its is represents the Sale of Receivables.

+ References

No definition available.

+ Details

Name:	air_SaleOfReceivablesLineItems
Namespace Prefix:	air_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow associated with the collection of receivables arising from the financing of goods and services.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromCollectionOfFinanceReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The face amount of all receivables that will be sold to other entities, including trade and loan receivables.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

+ Details

Name:	us-gaap_ReceivablesHeldForSaleAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_TypeOfArrangementAxis=air_PurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherNonoperatingIncomeExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: