Oil and Gas Producing Activities (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Oil and Gas Exploration and Production Industries Disclosures [Abstract]

Cost incurred in oil and gas exploration and development activities

Total costs incurred in crude oil and natural gas exploration and development activities, all within the U.S., were as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017		2016		2015
Property acquisition costs:
Unproved	$	4	$	32	$	348
Proved	—		—		—
Exploration costs:
Expensed	5		291		1,667
Capitalized	—		—		—
Development costs	1,815		—		370
Total costs incurred	$	1,824	$	323	$	2,385

Capitalized costs relating to oil and gas producing activities

The aggregate capitalized costs relative to crude oil and natural gas producing activities were as follows at the dates indicated (in thousands):

	December 31,
	2017		2016
Unproved crude oil and natural gas properties	$	—	$	—
Proved crude oil and natural gas properties	—		62,784
Subtotal	—		62,784
Accumulated depreciation, depletion and amortization	—		(56,426		)
Net capitalized cost	$	—	$	6,358

Proved developed and undeveloped oil and gas reserves

Proved developed and undeveloped reserves were as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017				2016				2015
	Natural		Crude		Natural		Crude		Natural		Crude
	Gas		Oil		Gas		Oil		Gas		Oil
	(Mcf)		(Bbls)		(Mcf)		(Bbls)		(Mcf)		(Bbls)
Total proved reserves:
Beginning of year	4,214		187		4,835		226		5,611		318
Revisions of previous estimates	—		—		65		24		27		(2	)
Crude oil and natural gas reserves sold	(4,067	)	(170	)	(175	)	(4	)	—		(3	)
Extensions, discoveries and other
reserve additions	42		6		151		18		86		13
Production	(189	)	(23	)	(662	)	(77	)	(889	)	(100	)
End of year	—		—		4,214		187		4,835		226

Components of proved oil and gas reserves

The components of our previously owned proved crude oil and natural gas reserves, all within the U.S., were as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017		2016		2015
	Natural	Crude	Natural	Crude	Natural	Crude
	Gas	Oil	Gas	Oil	Gas	Oil
	(Mcf)	(Bbls)	(Mcf)	(Bbls)	(Mcf)	(Bbls)
Proved developed reserves	—	—	4,214	187	4,813	223
Proved undeveloped reserves	—	—	—	—	22	3
Total proved reserves	—	—	4,214	187	4,835	226

Standardized measure of discounted future net cash flows

The standardized measure of discounted future net cash flows was as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017		2016			2015
Future gross revenues	$	—	$	17,938		$	23,040
Future costs:
Lease operating expenses	—		(12,421		)	(14,524		)
Development costs	—		(38		)	(103		)
Future net cash flows before income taxes	—		5,479			8,413
Discount at 10% per annum	—		(2,002		)	(2,987		)
Discounted future net cash flows before income taxes	—		3,477			5,426
Future income taxes, net of discount at 10% per annum	—		(1,217		)	(1,899		)
Standardized measure of discounted future net cash flows	$	—	$	2,260		$	3,527

Assumed market prices of oil and natural gas reserves and future net revenues

For such estimates, our independent petroleum engineers assumed market prices as presented in the table below:

	Year Ended December 31,
	2017		2016		2015
Market price:
Crude oil per barrel	$	—	$	38.34	$	45.83
Natural gas per thousand cubic feet (Mcf)	$	—	$	2.56	$	2.62

Effect of income taxes and discounting on the standardized measure of discounted future net cash flows

The effect of income taxes and discounting on the standardized measure of discounted future net cash flows was as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017		2016			2015
Future net cash flows before income taxes	$	—	$	5,479		$	8,413
Future income taxes	—		(1,918		)	(2,945		)
Future net cash flows	—		3,561			5,468
Discount at 10% per annum	—		(1,301		)	(1,941		)
Standardized measure of discounted future net cash flows	$	—	$	2,260		$	3,527

Principal sources of changes in the standardized measure of discounted future net flows

The principal sources of changes in the standardized measure of discounted future net cash flows were as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017			2016			2015
Beginning of year	$	2,260		$	3,527		$	15,744
Sale of crude oil and natural gas reserves	(2,732		)	(350		)	(54		)
Net change in prices and production costs	—			(1,391		)	(17,622		)
New field discoveries and extensions, net of future    production costs	94			275			292
Sales of crude oil and natural gas produced, net of production costs	(476		)	87			1,038
Net change due to revisions in quantity estimates	—			181			38
Accretion of discount	130			194			1,116
Production rate changes and other	(493		)	(945		)	(3,603		)
Net change in income taxes	1,217			682			6,578
End of year	$	—		$	2,260		$	3,527

Results of operations for oil and gas producing activities

The results of crude oil and natural gas producing activities, excluding corporate overhead and interest costs, were as follows for the periods indicated (in thousands):

	Year Ended December 31,
	2017			2016			2015
Revenues	$	1,427		$	3,410		$	5,063
Costs and expenses:
Production	(951		)	(3,337		)	(7,022		)
Producing property impairment	—			(30		)	(10,324		)
Exploration	—			—			(1,667		)
Depreciation, depletion and amortization	(423		)	(1,546		)	(5,066		)
Operating loss before income taxes	53			(1,503		)	(19,016		)
Income tax benefit (expense)	(19		)	526			6,656
Operating earnings (losses)	$	34		$	(977	)	$	(12,360	)