SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Accumulated Balances for Each Component of Other Comprehensive Income (Loss), Net of Tax (Parenthetical) (Details) - ASU 2016-01 $ in Millions	12 Months Ended
May 26, 2019 USD ($)
Retained earnings
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gains on available-for-sale securities reclassified to retained earnings	$ 0.6
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gains on available-for-sale securities reclassified to retained earnings	$ (0.6)

Amount, after tax and before adjustment, of unrealized holding gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Excludes unrealized gain (loss) on investment in debt security measured at amortized cost (held-to-maturity) from transfer to available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669646-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e637-108580

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