SUPPLEMENTAL INFORMATION - NATURAL GAS AND CRUDE OIL PROPERTIES Results of Operations for Natural Gas and Crude Oil Producing Activities (Unaudited) (Details) MBbls in Thousands, $ in Thousands, MMBbls in Millions	12 Months Ended
	Dec. 31, 2019 MBbls	Dec. 31, 2019 USD ($)	Dec. 31, 2019 MMBbls	Dec. 31, 2018 MBbls	Dec. 31, 2018 USD ($)	Dec. 31, 2018 MMBbls	Dec. 31, 2017 MBbls	Dec. 31, 2017 USD ($)	Dec. 31, 2017 MMBbls
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Undeveloped Reserves Converted to Developed | MBbls	0			0			0
Extensions, Discoveries, and Other Additions | MBbls	4,285			27,946			6,005
Purchases of Reserves | MBbls	1,761			60,360			86,778
Revisions of Previous Estimates | MBbls	112,147			55,011			52,457
Production | MBbls	(49,414)			(40,160)			(31,830)
Dispositions | MBbls	(2,868)			(11,121)			(1,900)
Total Revenues from Oil and Gas Producing Activities		$ 1,307,275			$ 1,389,961			$ 913,084
Lease operating expenses		142,248			130,957			89,641
Production taxes		80,754			90,357			60,717
Transportation, gathering and processing expenses		46,353			37,403			33,220
Results of Operations for Crude Oil and Natural Gas Producing Activities
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Natural gas, NGL and crude oil sales		1,307,275			1,389,961			913,084
Commodity price risk management		(162,844)			145,237			(3,936)
Total Revenues from Oil and Gas Producing Activities		1,144,431			1,535,198			909,148
Lease operating expenses		142,248			130,957			89,641
Production taxes		80,754			90,357			60,717
Transportation, gathering and processing expenses		46,353			37,403			33,220
Exploration Expense		4,054			6,204			47,334
Impairment of Oil and Gas Properties		38,536			458,397			285,887
Depreciation, Depletion and Amortization		638,499			551,265			462,482
Accretion of Asset Retirement Obligations		6,117			5,075			6,306
(Gain) loss on Sale of Properties and Equipment		9,734			394			(766)
Total Expense from Oil and Gas Producing Activities		966,295			1,280,052			984,821
Results of Operations of Natural Gas and Crude Oil Producing Activities, Income before Income Taxes		178,136			255,146			(75,673)
Provision for Income Taxes		(9,869)			(185,667)			47,247
Results of operations for natural gas and crude oil producing activities, excluding corporate overhead and interest costs		$ 168,267			$ 69,479			$ (28,426)
Proved Developed Reserves [Member]
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Undeveloped Reserves Converted to Developed	52,169		52.2	58,294		58.3	54,648		54.6
Extensions, Discoveries, and Other Additions	4,285		4.3	7,874		7.9	2,292		2.3
Purchases of Reserves	441		0.4	8,758		8.8	1,305		1.3
Revisions of Previous Estimates | MBbls	27,452			6,284			18,291
Production	49,414		49.4	40,160		40.2	31,830		31.8
Dispositions	474		0.5	4,486		4.5	20
Proved Undeveloped Reserves [Member]
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Undeveloped Reserves Converted to Developed | MBbls	(52,169)			(58,294)			(54,648)
Extensions, Discoveries, and Other Additions	0			20,072		20.1	3,713		3.7
Purchases of Reserves | MBbls	1,320			51,602			85,473
Acquisition Of Reserves Acreage Swaps | MMBbls			1.3			47.6			85.5
Revisions of Previous Estimates	84,695		74.2	48,727		71.7	34,166		89.8
Production | MBbls	0			0			0
Dispositions	2,394		2.4	6,635		6.6	1,880		1.9