SUPPLEMENTAL INFORMATION - NATURAL GAS AND CRUDE OIL PROPERTIES Schedule of Developed and Undeveloped Reserves (Unaudited) (Details) MBbls in Thousands, MMBbls in Millions	12 Months Ended
	Dec. 31, 2019 MBbls	Dec. 31, 2019 Rate MBbls	Dec. 31, 2019 MBbls	Dec. 31, 2019 MBbls MMBbls	Dec. 31, 2018 Rate MBbls	Dec. 31, 2018 MBbls	Dec. 31, 2018 MBbls MMBbls	Dec. 31, 2017 Rate MBbls	Dec. 31, 2017 MBbls	Dec. 31, 2017 MBbls MMBbls	Dec. 31, 2016 MBbls
Schedule of Developed and Undeveloped Reserves [Line Items]
Document Period End Date	Dec. 31, 2019
Proved Developed and Undeveloped Reserves, Net	610,864	610,864	610,864	610,864	544,953	544,953	544,953	452,917	452,917	452,917	341,407
Undeveloped Reserves Converted to Developed			0			0			0
Revisions of Previous Estimates			112,147			55,011			52,457
Extensions, Discoveries, and Other Additions			4,285			27,946			6,005
Purchases of Reserves			1,761			60,360			86,778
Dispositions			2,868			11,121			1,900
Production			49,414			40,160			31,830
Proved developed and undeveloped reserves percent increase or decrease | Rate		12.00%
Increase or Decrease in Proved Reserves | MMBbls							92.0
Proved Undeveloped Reserves [Member]
Schedule of Developed and Undeveloped Reserves [Line Items]
Majority of upward downward revision of our previous estimate of proved reserves | MMBbls				23.4			3.8			2.9
Proved Developed and Undeveloped Reserves, Net	396,870	396,870	396,870	396,870	365,418	365,418	365,418	309,946	309,946	309,946	243,122
Undeveloped Reserves Converted to Developed			(52,169)			(58,294)			(54,648)
Revisions of Previous Estimates			84,695	74.2		48,727	71.7		34,166	89.8
Extensions, Discoveries, and Other Additions			0			20,072	20.1		3,713	3.7
Purchases of Reserves			1,320			51,602			85,473
Acquisition Of Reserves Acreage Swaps | MMBbls				1.3			47.6			85.5
Dispositions			(2,394)	(2.4)		(6,635)	(6.6)		(1,880)	(1.9)
Production			0			0			0
Actual PUD conversion rate | Rate		14.00%			19.00%			23.00%
Upward Downward revisions Wattenberg Field related to PUDs that are no longer in our core drilling area | MMBbls				12.9			26.8			58.5
Proved Developed Reserves [Member]
Schedule of Developed and Undeveloped Reserves [Line Items]
Proved Developed and Undeveloped Reserves, Net	213,994	213,994	213,994	213,994	179,535	179,535	179,535	142,971	142,971	142,971	98,285
Undeveloped Reserves Converted to Developed			52,169	52.2		58,294	58.3		54,648	54.6
Revisions of Previous Estimates			27,452			6,284			18,291
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
Dispositions			(474)	(0.5)		(4,486)	(4.5)		(20)
Production			(49,414)	(49.4)		(40,160)	(40.2)		(31,830)	(31.8)
Upward (Downward) Revision due to change in SEC pricing | MMBbls				17.3			11.4			17.7
Additional Change in Reserves | MMBbls				10.2			5.1			0.6
Crude Oil Equivalent (Boe)
Schedule of Developed and Undeveloped Reserves [Line Items]
Proved Developed and Undeveloped Reserves, Net	610,864	610,864	610,864	610,864	544,953	544,953	544,953	452,917	452,917	452,917	341,407
Revisions of Previous Estimates			112,147			55,011			52,457
Extensions, Discoveries, and Other Additions			4,285			27,946			6,005
Purchases of Reserves			1,761			60,360			86,778
Dispositions			(2,868)			(11,121)			(1,900)
Production			(49,414)			(40,160)			(31,830)
Crude Oil [Member]
Schedule of Developed and Undeveloped Reserves [Line Items]
Proved Developed and Undeveloped Reserves, Net	197,255	197,255	197,255	197,255	190,349	190,349	190,349	154,842	154,842	154,842	118,169
Revisions of Previous Estimates			25,875			26,548			28,334
Extensions, Discoveries, and Other Additions			1,056			8,786			2,923
Purchases of Reserves			553			19,644			18,971
Dispositions			(1,412)			(2,507)			(653)
Production			(19,166)			(16,964)			(12,902)
Year-over-Year Activity [Domain]
Schedule of Developed and Undeveloped Reserves [Line Items]
Proved developed and undeveloped reserves percent increase or decrease | Rate					20.00%			33.00%