GOODWILL AND INTANGIBLES - Estimated Intangible Asset Amortization Expense (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	$ 2,036
2020	7,710
2021	7,205
2022	6,975
2023	5,698
Later	40,450
Total estimated future intangible asset amortization expense	70,074
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	1,005
2020	4,022
2021	4,022
2022	4,022
2023	4,022
Later	18,866
Total estimated future intangible asset amortization expense	35,959
Production and Supply Contracts
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	516
2020	1,741
2021	1,397
2022	1,242
2023	0
Later	0
Total estimated future intangible asset amortization expense	4,896
Internally Developed Software Intangible
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	139
2020	445
2021	284
2022	211
2023	179
Later	84
Total estimated future intangible asset amortization expense	1,342
Licenses
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	360
2020	1,439
2021	1,439
2022	1,437
2023	1,434
Later	21,315
Total estimated future intangible asset amortization expense	27,424
Trade Names
Finite-Lived Intangible Assets [Line Items]
January 1, 2019 through March 31, 2019	16
2020	63
2021	63
2022	63
2023	63
Later	185
Total estimated future intangible asset amortization expense	$ 453