Supplemental Financial Data - Oil and Gas Producing Activities (unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

Extractive Industries [Abstract]

Schedule of proved undeveloped and developed oil and gas reserves expected to be recovered from new wells

	2018												2017
	Oil			Natural Gas			NGL			Total			Oil			Natural Gas			NGL		Total
	MBbls			MMcf			MBbls			MMcfe			MBbls			MMcf			MBbls		MMcfe
Proved reserves, beginning of year		919			81,702			-			87,216			882			74,265			-		79,557
Revisions of previous estimates		(2,803	)		1,832			(1,147	)		(21,868	)		107			12,199			-		12,841
Extensions and discoveries		-			-			-			-			16			136			-		232
Production		(451	)		(4,798	)		(33	)		(7,702	)		(86	)		(4,898	)		-		(5,414	)
Purchases of reserves in-place		21,233			376,664			3,103			522,680			-			-			-		-
Sales of reserves in-place		-			-			-			-			-			-			-		-
Proved reserves, end of year		18,898			455,400			1,923			580,326			919			81,702			-		87,216
Proved developed reserves at:
End of year		14,336			450,424			1,472			545,272			903			81,702			-		87,216
Proved undeveloped reserves at:
End of year		4,562			4,976			451			35,054			16			-			-		96

Schedule of aggregate capitalized costs relating to oil and gas producing activities

(in thousands)	2018			2017
Oil and gas properties:
Proved oil and gas properties	$	347,059		$	114,893
Unproved properties not subject to depletion		5,416			1,947
Accumulated depreciation, depletion, amortization and impairment		(98,604	)		(80,715	)
Total	$	253,871		$	36,125

Schedule of costs incurred in oil and gas property acquisition, exploration, and development activities

(in thousands)	2018		2017
Property acquisition costs:
Unevaluated properties	$	3,464	$	1
Proved properties and gathering facilities		63,517		289
Development costs		2,074		952
Gathering facilities		460		43
Asset retirement obligation		14,085		2,309
Total	$	83,600	$	3,594

Schedule of company's investment in unproved properties

	2018		2017		2016  and Prior
(in thousands)
Acquisition costs	$	3,464	$	1	$	1,946

Schedule of results of operations from oil and gas producing activities

(in thousands)
	2018		2017
Revenues:
Oil and gas sales, including commodity derivative gains and losses	$	52,946	$	22,439
Expenses:
Production expenses		22,226		9,589
Depletion expense		7,305		2,157
Accretion of asset retirement obligations		868		307
Total expenses		30,399		12,053
Results of operations from oil and gas producing activities	$	22,547	$	10,386
Depletion rate per Mcfe	$	0.89	$	0.40

Schedule of estimate of the current market value of the Company's proved reserves

(in thousands)	December 31,
	2018			2017
Future cash inflows	$	2,878,392		$	283,664
Future production costs		(1,538,870	)		(119,501	)
Future development costs		(76,852	)		(210	)
Future income taxes		(258,277	)		(35,482	)
Future net cash flows		1,004,393			128,471
10% annual discount		(612,325	)		(71,389	)
Standardized measure of discounted future net cash flows	$	392,068		$	57,082

Schedule of discounted future cash flows relating to proved oil and gas reserves

	December 31,
	2018			2017
(in thousands)
Standardized measure of discounted future net cash flows, beginning of period	$	57,082		$	44,711
Sales of oil and gas, net of production costs and taxes		(25,681	)		(10,038	)
Price revisions		133,789			17,588
Extensions, discoveries and improved recovery, less related costs		-			298
Changes in estimated future development costs		(32,711	)		(324	)
Development costs incurred during the period		926			804
Quantity revisions		(23,484	)		11,196
Accretion of discount		5,708			4,471
Net changes in future income taxes		(89,117	)		(7,425	)
Purchases of reserves-in-place		391,877			-
Sales of reserves-in-place		-			-
Changes in production rate timing and other		(26,321	)		(4,199	)
Standardized measure of discounted future net cash flows, end of period	$	392,068		$	57,082

Schedule of weighted averaged adjusted prices

	2018		2017
Oil (per Bbl)	$	65.56	$	51.34
Natural Gas (per Mcf)	$	3.10	$	2.98