SUPPLEMENTAL INFORMATION - QUARTERLY FINANCIAL INFORMATION QUARTERLY FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Revenues	$ 265,022	$ 365,943	$ 390,658	$ 134,500	$ 794,811	$ 280,717	$ 212,531	$ 260,600	$ 1,156,123	$ 1,548,659	$ 921,616
Costs, expenses and other:
Total cost, expenses and other	267,713	321,562	280,623	275,120	538,626	270,593	400,770	260,924	1,145,018	1,470,913	1,159,868
Operating Income (Loss)	(2,691)	44,381	110,035	(140,620)	256,185	10,124	(188,239)	(324)	11,105	77,746	(238,252)
Income (loss) before income taxes	(20,111)	26,570	91,135	(157,588)	238,024	(7,310)	(205,580)	(17,705)	(59,994)	7,429	(339,432)
Net income (loss)	$ (20,952)	$ 15,908	$ 68,548	$ (120,176)	$ 178,853	$ (3,434)	$ (160,257)	$ (13,139)	$ (56,672)	$ 2,023	$ (127,504)
Basic
Basic	$ (0.34)	$ 0.25	$ 1.04	$ (1.82)	$ 2.71	$ (0.05)	$ (2.43)	$ (0.20)	$ (0.89)	$ 0.03	$ (1.94)
Diluted
Diluted	$ (0.34)	$ 0.25	$ 1.04	$ (1.82)	$ 2.71	$ (0.05)	$ (2.43)	$ (0.20)	$ (0.89)	$ 0.03	$ (1.94)
Deferred income taxes									$ (2,256)	$ 6,105	$ (203,685)