Contingencies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
May 31, 2014
Commitments And Contingencies Disclosure [Line Items]
Standby letters of credit	$ 3.3
Benton County Foods, LLC [Member]
Commitments And Contingencies Disclosure [Line Items]
Membership interest	100.00%

The fair value, as of the date of each statement of financial position presented, of securities that are restricted as collateral under letter of credit agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

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