Capital Stock and Stock-Based Awards (Details) - Schedule of restricted stock units under the management stock purchase plan - Management Stock Purchase Plan [Member] - $ / shares	12 Months Ended
May 31, 2017	May 31, 2016	May 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (Shares)	42,565	58,633	67,027
Purchase price per unit (in Dollars per share)	$ 28.49	$ 30.38	$ 23.79

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration