REVENUE RECOGNITION AND RELATED ALLOWANCES - Accruals and Allowances (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Accruals and allowances
Beginning balance	$ 59,946
Ending balance	86,418
Chargebacks
Accruals and allowances
Beginning balance	49,882	$ 39,007
Accruals/Adjustments	288,538	187,843
Credits Taken Against Reserve	(262,531)	(188,504)
Ending balance	75,889	38,346
Government Rebates
Accruals and allowances
Beginning balance	8,901	8,974
Accruals/Adjustments	14,288	12,723
Credits Taken Against Reserve	(11,511)	(12,513)
Ending balance	11,678	9,184
Returns
Accruals and allowances
Beginning balance	16,595	12,552
Accruals/Adjustments	22,744	13,392
Credits Taken Against Reserve	(16,089)	(9,999)
Ending balance	23,250	15,945
Administrative Fees and Other Rebates
Accruals and allowances
Beginning balance	8,281	7,353
Accruals/Adjustments	27,383	27,476
Credits Taken Against Reserve	(27,287)	(26,927)
Ending balance	8,377	7,902
Prompt Payment Discounts
Accruals and allowances
Beginning balance	2,549	2,009
Accruals/Adjustments	10,248	7,962
Credits Taken Against Reserve	(9,442)	(7,714)
Ending balance	$ 3,355	$ 2,257

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Amount of increase (decrease) in valuation and qualifying accounts and reserves from adjustment.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

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Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column B))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09(Column E))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

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Amount of decrease in valuation and qualifying accounts and reserves.

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