SEGMENT INFORMATION - Major Customers (Details) - Customer concentration - Revenues	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
McKesson Corporation
Segment reporting information
Concentration risk, percentage	17.00%	17.00%	18.00%
AmerisourceBergen Corporation
Segment reporting information
Concentration risk, percentage	17.00%	16.00%	18.00%
Cardinal Health, Inc.
Segment reporting information
Concentration risk, percentage	13.00%	14.00%	13.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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