SUPPLEMENTAL CASH FLOW INFORMATION - Schedule of supplemental cash flow information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental cash flow information:
Cash interest paid	$ 12,885	$ 19,660
Less: capitalized interest	1,060	491
Interest paid (net of capitalized interest)	11,825	19,169
Noncash investing and financing activities:
Capital expenditures in trade accounts payable (period-end accruals)	5,613	$ 13,765
Series A Preferred Units
Noncash investing and financing activities:
Accretion of Subsidiary Series A Preferred Units	$ 2,438