SUPPLEMENTAL INFORMATION - NATURAL GAS AND CRUDE OIL PROPERTIES Changes in Estimated Proved Reserves (Unaudited) (Details) Mcf in Thousands	12 Months Ended
	Dec. 31, 2017 Rate Mcf bbl	Dec. 31, 2016 Rate Mcf bbl	Dec. 31, 2015 Rate Mcf bbl	Dec. 31, 2014 Mcf bbl
Reserve Quantities [Line Items]
Proved Reserves	452,917,000	341,407,000	272,825,000	250,129,000
Production	(31,830,000)	(22,176,000)	(15,369,000)
Undeveloped Reserves Converted to Developed	0	0	0
Purchases of Reserves	86,778,000	133,583,000	76,000
Dispositions	(1,900,000)	(1,725,000)	(34,000)
Negative revisions due to PUD locations dropped from 5 year development plan	57,700,000.0
Extensions, Discoveries, and Other Additions	6,005,000	1,531,000	131,494,000
Revisions of Previous Estimates	52,457,000	(42,631,000)	(93,471,000)
Increase or Decrease in Proved Reserves	111,500,000	0	22,700,000
Crude Oil (Bbls)
Reserve Quantities [Line Items]
Proved Reserves	154,842,000	118,169,000	98,975,000	100,515,000
Production	(12,902,000)	(8,728,000)	(6,984,000)
Purchases of Reserves	18,971,000	50,126,000	17,000
Dispositions	(653,000)	(601,000)	(12,000)
Extensions, Discoveries, and Other Additions	2,923,000	494,000	48,707,000
Revisions of Previous Estimates	28,334,000	(22,097,000)	(43,268,000)
Proved Developed Reserves	46,862,000	30,013,000	26,257,000
Proved Undeveloped Reserve	107,980,000	88,156,000	72,718,000
Natural Gas (Mcf)
Reserve Quantities [Line Items]
Proved Reserves | Mcf	1,154,294	833,697	660,737	536,972
Production | Mcf	(71,689)	(51,730)	(33,302)
Purchases of Reserves | Mcf	289,223	305,224	215
Dispositions | Mcf	(4,597)	(4,202)	(82)
Extensions, Discoveries, and Other Additions | Mcf	11,541	4,094	311,709
Revisions of Previous Estimates | Mcf	96,119	(80,426)	(154,775)
Proved Developed Reserves | Mcf	365,332	264,452	175,367
Proved Undeveloped Reserve | Mcf	788,962	569,245	485,370
Natural Gas Liquids (Bbls)
Reserve Quantities [Line Items]
Proved Reserves	105,692,000	84,288,000	63,727,000	60,119,000
Production	(6,981,000)	(4,826,000)	(2,835,000)
Purchases of Reserves	19,604,000	32,586,000	23,000
Dispositions	(481,000)	(424,000)	(8,000)
Extensions, Discoveries, and Other Additions	1,158,000	355,000	30,835,000
Revisions of Previous Estimates	8,104,000	(7,130,000)	(24,407,000)
Proved Developed Reserves	35,220,000	24,196,000	15,011,000
Proved Undeveloped Reserve	70,472,000	60,092,000	48,716,000
Crude Oil Equivalent (Boe)
Reserve Quantities [Line Items]
Proved Reserves	452,917,000	341,407,000	272,825,000	250,129,000
Production	(31,830,000)	(22,176,000)	(15,369,000)
Purchases of Reserves	86,778,000	133,583,000	76,000
Dispositions	(1,900,000)	(1,725,000)	(34,000)
Extensions, Discoveries, and Other Additions	6,005,000	1,531,000	131,494,000
Revisions of Previous Estimates	52,457,000	(42,631,000)	(93,471,000)
Proved Developed Reserves	142,971,000	98,284,000	70,496,000
Proved Undeveloped Reserve	309,946,000	243,122,000	202,329,000
Increase or Decrease in Proved Reserves			15,369,000
Year-over-Year Activity [Domain]
Reserve Quantities [Line Items]
Proved developed and undeveloped reserves percent increase or decrease | Rate	32.6619%	25.00%
Undeveloped Reserves Converted to Developed		32,200,000.0	29,090,000
Estimated PUD conversion rate for following year | Rate	16.00%	26.00%
Negative revisions due to PUD locations dropped from 5 year development plan	0.7
Extensions, Discoveries, and Other Additions	93,900,000.0		131,494,000
Revisions of Previous Estimates			93,471,000
Estimated PUD conversion rate | Rate		19.00%	16.00%
Actual PUD conversion rate | Rate	23.00%	16.00%	17.00%
2015 PUD Reserves [Member]
Reserve Quantities [Line Items]
Production		(61)