Note 9 - Business Segment Reporting - Sales by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Nov. 25, 2018	Nov. 26, 2017	Nov. 25, 2018	Nov. 26, 2017
Segment sales	$ 124,912	$ 122,461	$ 249,580	$ 238,242
CANADA
Segment sales	20,300	17,300	40,200	35,600
BELGIUM
Segment sales	500	500	2,500	2,700
IRELAND
Segment sales	1,200	800	2,300	1,600
DENMARK
Segment sales		500	200	700
SWITZERLAND
Segment sales	500		600
MEXICO
Segment sales	100	200	100	300
All Other Countries [Member]
Segment sales	$ 600	$ 1,100	$ 1,100	$ 1,200

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

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