RESTRUCTURING - Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Restructuring Plan 2018
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	$ 1,192
Charges	2,699
Cash payments	(1,610)
Non-cash settlement and other	(2,281)
Restructuring reserve, ending	0	$ 1,192
Restructuring Plan 2018 \| Redundancy and Employee Severance and Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	904
Charges	2,699
Cash payments	(1,610)
Non-cash settlement and other	(1,993)
Restructuring reserve, ending	0	904
Restructuring Plan 2018 \| Lease Loss Reserves and Contractual Obligations
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	288
Charges	0
Cash payments	0
Non-cash settlement and other	(288)
Restructuring reserve, ending	0	288
Restructuring Plan 2016
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	1,591	1,323
Charges		(40)
Cash payments		308
Non-cash settlement and other	(1,591)
Restructuring reserve, ending	0	1,591
Restructuring Plan 2016 \| Redundancy and Employee Severance and Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	0	229
Charges		0
Cash payments		(229)
Non-cash settlement and other	0
Restructuring reserve, ending	0	0
Restructuring Plan 2016 \| Lease Loss Reserves and Contractual Obligations
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning	1,591	1,094
Charges		(40)
Cash payments		537
Non-cash settlement and other	(1,591)
Restructuring reserve, ending	$ 0	$ 1,591

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 17
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3367-108585

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

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-Publisher FASB
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-Topic 420
-SubTopic 10
-Section S99
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of decrease in the reserve for full or partial settlement through consideration other than cash.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 420
-SubTopic 10
-Section S99
-Paragraph 2
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