SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Allowance for credit losses (Details) $ in Thousands	3 Months Ended
Mar. 29, 2020 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Beginning balance	$ 4,288
Cumulative-effect adjustment	6,379
Provision for doubtful accounts	2,660
Write-offs, net	(1,093)
Ending balance	6,379
Cumulative-effect adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Beginning balance	524
Cumulative-effect adjustment	$ 524

Amount of allowance for credit loss on accounts receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5074-111524

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919249-210447

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118955202&loc=SL82895884-210446

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

+ References

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