Supplemental Information on Oil and Natural Gas Operations (Unaudited) - Oil and Natural Gas Reserves (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Boe well ft bbl Mcf	Dec. 31, 2015 USD ($) Boe well acquisition bbl Mcf	Dec. 31, 2014 USD ($) well acquisition bbl Mcf	Dec. 31, 2013 bbl Mcf
Reserve Quantities [Line Items]
Number of Wells Developed, Mineral Interest	30
Number of New Wells Developed, Mineral Interest	30
Proved Developed And Undeveloped Reserves Revisions Of Previous Estimates Increase(Decrease) Due to Pricing	(5,978,000)
Proved Developed And Undeveloped Reserves Revisions Of Previous Estimates Increase (Decrease) Due to Reclassification of Proved Undeveloped Locations	(7,253,000)
Proved Developed and Undeveloped Reserves (Volume)
Extensions and discoveries	79,824,000
Purchase of reserves in place	4,556,000
Number of major acquisitions | acquisition		1	2
Number of existing vertical wells | well		136	280
Number of existing horizontal wells | well		4	6
Number of vertical wells acquired | well		3
Number of horizontal PUDs included in the acquired reserves | well		0	0
Number of vertical wells developed, working interest | well		2	18
Number of horizontal wells developed, working interest | well	17	119	103
Number of vertical wells developed, mineral interest | well			1
Number of horizontal wells developed, mineral interest | well	2	16	14
Number of Vertical Wells Developed | well		2	19
Number of Horizontal Wells Developed | well		135	117
Number of vertical wells developed, proved undeveloped category | well		1	5
Number of horizontal wells developed, proved undeveloped category | well			66
Number of vertical locations downgraded | well		89	73
Proved Undeveloped Reserves, Vertical Wells Downgraded, Working Interest | well		80
Proved Undeveloped Reserves, Horizontal Wells Downgraded, Working Interest | well		22
Proved Undeveloped Reserves, Vertical Wells Downgraded, Mineral Interest | well		22
Proved undeveloped reserves, increase (Energy) | Boe	21,587,000
Proved Undeveloped Reserves (Energy)
Beginning proved undeveloped reserves at December 31, 2015 | Boe	64,767,043
Undeveloped reserves transferred to developed | Boe	(13,383,000)
Revisions | Boe	(5,210,000)
Extensions and discoveries | Boe	40,180,000
Ending proved undeveloped reserves at December 31, 2016 | Boe	86,354,000	64,767,043
Percent of proved undeveloped reserve extensions that are more than one offset away from existing producing wells	41.00%
Distance from producing wells | ft	2,000
Downward revisions | Boe	5,210,000
Proved undeveloped reserves, planned development period	5 years	5 years
Capital expenditures towards development of proved undeveloped reserves | $	$ 47,575	$ 42,749	$ 86,097
Development Wells Drilled, Net Productive	59
Proved Undeveloped Reserves Number of Wells Added	51
Martin County, Texas [Member]
Proved Developed and Undeveloped Reserves (Volume)
Number of major acquisitions | acquisition			1
Oil [Member]
Proved Developed and Undeveloped Reserves (Volume)
Beginning of the period	105,978,711	75,689,589	42,600,852
Extensions and discoveries	55,069,092	48,725,132	37,068,820
Revisions of previous estimates	(12,482,657)	(12,130,474)	(6,784,560)
Purchase of reserves in place	2,170,774	2,775,599	8,186,053
Production	(11,561,920)	(9,081,135)	(5,381,576)
End of the period	139,174,000	105,978,711	75,689,589
Proved Developed Reserves (Volume)	79,457,000	60,569,398	43,885,835	19,789,965
Proved Undeveloped Reserves (Volume)	59,717,000	45,409,313	31,803,754	22,810,887
Natural Gas Liquids [Member]
Proved Developed and Undeveloped Reserves (Volume)
Beginning of the period	26,004,144	18,541,932	10,705,724
Extensions and discoveries	13,962,103	12,055,631	7,828,094
Revisions of previous estimates	(1,887,643)	(4,080,886)	649,476
Purchase of reserves in place	1,454,836	1,165,090	360,536
Production	(2,399,440)	(1,677,623)	(1,001,898)
End of the period	37,134,000	26,004,144	18,541,932
Proved Developed Reserves (Volume)	22,080,000	15,418,353	11,221,428	4,973,493
Proved Undeveloped Reserves (Volume)	15,054,000	10,585,791	7,320,504	5,732,231
Natural Gas [Member]
Proved Developed and Undeveloped Reserves (Volume)
Beginning of the period | Mcf	149,502,744	111,605,260	61,679,496
Extensions and discoveries | Mcf	64,758,390	53,452,948	52,099,252
Revisions of previous estimates | Mcf	(34,518,746)	(14,726,160)	(17,726,552)
Purchase of reserves in place | Mcf	5,582,053	7,101,933	19,898,649
Production | Mcf	(10,428,441)	(7,931,237)	(4,345,585)
End of the period | Mcf	174,896,000	149,502,744	111,605,260
Proved Developed Reserves (Volume) | Mcf	105,399,000	96,871,109	68,264,113	31,428,756
Proved Undeveloped Reserves (Volume) | Mcf	69,497,000	52,631,635	43,341,147	30,250,740