REVENUE RECOGNITION AND RELATED ALLOWANCES - Allowances (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Accruals and allowances
Beginning balance	$ 100,328
Ending balance	92,130
Chargebacks
Accruals and allowances
Beginning balance	88,746	$ 49,882
Accruals/Adjustments	214,125	181,986
Credits Taken Against Reserve	(220,776)	(169,345)
Ending balance	82,095	62,523
Government Rebates
Accruals and allowances
Beginning balance	7,826	8,901
Accruals/Adjustments	12,980	7,519
Credits Taken Against Reserve	(12,066)	(6,703)
Ending balance	8,740	9,717
Returns
Accruals and allowances
Beginning balance	27,155	16,595
Accruals/Adjustments	21,058	14,103
Credits Taken Against Reserve	(16,309)	(10,695)
Ending balance	31,904	20,003
Administrative Fees and Other Rebates
Accruals and allowances
Beginning balance	8,906	8,281
Accruals/Adjustments	32,207	17,392
Credits Taken Against Reserve	(33,071)	(17,161)
Ending balance	8,042	8,512
Prompt Payment Discounts
Accruals and allowances
Beginning balance	3,839	2,549
Accruals/Adjustments	13,315	6,551
Credits Taken Against Reserve	(13,682)	(6,277)
Ending balance	$ 3,472	$ 2,823

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+ 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)
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Amount of valuation and qualifying accounts and reserves.

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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))
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-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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