PROPERTY AND EQUIPMENT (Schedule of Property and Equipment) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Oil and natural gas properties	$ 10,551,713	$ 10,026,836
Other depreciable property and equipment	90,712	87,146
Land	5,521	5,521
Total property and equipment	10,647,946	10,119,503
Accumulated depletion, depreciation, amortization and impairment	(5,063,413)	(4,640,098)
Property and equipment, net	$ 5,584,533	$ 5,479,405