SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash paid for interest (net of capitalized interest)	$ 52,329	$ 54,539
Cash paid for income taxes	159	180
Capitalized interest	1,788	1,029
Capital expenditures incurred but not yet paid	$ 64,700	$ 49,600