SUPPLEMENTAL INFORMATION - NATURAL GAS AND CRUDE OIL PROPERTIES Principal Sources of Change in Standardized Measure of Discounted Future Net Cash Flows (Unuadited) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Principal Sources of Change:
Standardized Measure of Discounted Future Net Cash Flow of Proved Oil and Gas Reserves, Period Increase (Decrease)		$ 3,310,334,000	$ 4,447,716,000	$ 2,880,105,000	$ 1,420,629,000
Sales of natural gas, NGL and crude oil production, net of production costs		(1,037,920,000)	(1,131,244,000)	(729,506,000)
Net changes in prices and production costs	[1]	(2,122,538,000)	936,077,000	841,713,000
Extensions, discoveries and improved recovery, less related costs		39,606,000	190,084,000	47,240,000
Sales of reserves		(14,533,000)	(42,362,000)	(2,613,000)
Purchases of reserves		18,816,000	467,807,000	224,483,000
Development costs incurred during the period		605,753,000	462,088,000	419,047,000
Revisions of previous quantity estimates		538,242,000	631,198,000	484,431,000
Changes in estimated income taxes		346,826,000	(232,002,000)	(138,560,000)
Net change in future development costs		206,003,000	(123,663,000)	25,183,000
Accretion of discount		532,127,000	583,744,000	167,487,000
Timing and other		(249,764,000)	(174,116,000)	120,571,000
Notes to Changes in SMOG [Abstract]
Weighted-Average price, net of production cost		$ 16.18	$ 23.44	$ 20.08

[1] Our weighted-average price, net of production costs per Boe, in our 2019 reserve report decreased to $16.18 as compared to $23.44 for 2018 and $20.08 for 2017.