QUARTERLY RESULTS OF OPERATIONS (UNAUDITED) (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
Quarterly Financial Information Disclosure [Abstract]
Total Revenues	$ 59,013	$ 233,883	$ 186,440	$ (6,934)	$ 443,196	$ 102,269	$ 66,846	$ 66,613	$ 472,402	$ 678,924	$ 209,320
Gain (Loss) on Derivative Instruments, Net	(101,697)	75,892	36,591	(139,623)	290,628	(43,148)	(42,203)	(20,271)	(128,837)	185,006	(14,667)
Operating Expenses	121,538	112,784	94,200	88,371	88,387	66,673	50,528	40,708
Income (Loss) from Operations	(62,525)	121,100	92,239	(95,305)	354,809	35,597	16,318	25,905	55,509	432,628	60,495
Other Nonoperating Income (Expense)	(45,412)	(26,719)	(47,840)	(11,857)	(136,571)	(16,618)	(112,866)	(22,940)
Income Tax Benefit	0	0	0	0	(55)	0	0	0	0	(55)	(1,570)
Net Income (Loss)	$ (107,937)	$ 94,381	$ 44,399	$ (107,162)	$ 218,292	$ 18,979	$ (96,547)	$ 2,965	$ (76,318)	$ 143,689	$ (9,194)
Net Income (Loss) Per Common Share - Basic (in dollars per share)	$ (0.27)	$ 0.24	$ 0.12	$ (0.29)	$ 0.58	$ 0.06	$ (0.49)	$ 0.05	$ (0.20)	$ 0.61	$ (0.15)
Net Income (Loss) Per Common Share - Diluted (in dollars per share)	$ (0.27)	$ 0.24	$ 0.12	$ (0.29)	$ 0.58	$ 0.06	$ (0.49)	$ 0.05	$ (0.20)	$ 0.61	$ (0.15)