SEGMENT INFORMATION - EBITDA Expense Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reconciliation of consolidated Segment Adjusted EBITDA Expense to operating expenses (excluding depreciation, depletion and amortization)
Segment Adjusted EBITDA Expense	$ 238,279	$ 251,786	$ 499,773	$ 515,274
Other income	389	161	1,687	252
Operating expenses (excluding depreciation, depletion and amortization)	$ 238,668	$ 251,947	$ 501,460	$ 515,526