INTANGIBLE ASSETS AND GOODWILL - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020	May 20, 2020	Dec. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 24,783	$ 101,774
Intangible assets carrying value	200,082	400,535
Market capitalization	38,000		$ 72,000
Zyla Life Sciences
Finite-Lived Intangible Assets [Line Items]
Goodwill	17,432			$ 14,147
INDOCIN Products | Zyla Life Sciences
Finite-Lived Intangible Assets [Line Items]
Intangible assets fair value				154,100
SPRIX | Zyla Life Sciences
Finite-Lived Intangible Assets [Line Items]
Intangible assets fair value				39,000
OXAYDO | Zyla Life Sciences
Finite-Lived Intangible Assets [Line Items]
Intangible assets fair value				$ 300
Product rights | INDOCIN Products
Finite-Lived Intangible Assets [Line Items]
Intangible assets carrying value	146,288	0
Product rights | SPRIX
Finite-Lived Intangible Assets [Line Items]
Intangible assets carrying value	35,611	0
Product rights | OXAYDO
Finite-Lived Intangible Assets [Line Items]
Intangible assets carrying value	117	0
Product rights | NUCYNTA
Finite-Lived Intangible Assets [Line Items]
Intangible assets impairment loss		189,800
Intangible assets carrying value	$ 0	$ 374,996			$ 564,800