Business Segment Reporting - Sales by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Nov. 24, 2019	Nov. 25, 2018	Nov. 24, 2019	Nov. 25, 2018
Segment Reporting Information [Line Items]
Net sales	$ 142,593	$ 124,557	$ 281,307	$ 249,225
Canada
Segment Reporting Information [Line Items]
Net sales	18,400	20,300	39,100	40,200
Belgium
Segment Reporting Information [Line Items]
Net sales	3,100	500	3,100	2,500
Ireland
Segment Reporting Information [Line Items]
Net sales	1,100	1,200	2,500	2,300
All Other Countries
Segment Reporting Information [Line Items]
Net sales	$ 2,000	$ 1,200	$ 3,400	$ 2,000

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
-Paragraph 5
-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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration