Disclosures About Oil and Gas Producing Activities (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Oil And Gas Exploration And Production Industries Disclosures [Abstract]

Analyses of changes in proven reserves

	United States
	Oil (MBbls)			Natural Gas (MMcf)			NGLs (MBbls)
Reserves, December 31, 2013		34,119			3,409,742			—
Extensions, discoveries and additions		34,275			866,513			210
Sales		—			(239,290	)		—
Acquisitions		9,381			1,345,964			21,740
Production		(3,409	)		(228,517	)		—
Revisions		(6,600	)		(323,218	)		43
Reserves, December 31, 2014		67,766			4,831,194			21,993
Extensions, discoveries and additions		166			17,415			3
Sales		—			—			—
Acquisitions		—			—			—
Production		(3,533	)		(268,954	)		—
Revisions		(42,224	)		(2,243,375	)		(12,156	)
Reserves, December 31, 2015		22,175			2,336,280			9,840
Extensions, discoveries and additions		3,519			251,634			530
Sales		—			—			—
Acquisitions		—			—			—
Production		(2,912	)		(264,278	)		—
Revisions		(1,307	)		(2,023	)		(467	)
Reserves, December 31, 2016		21,475			2,321,613			9,903

	United States
	Oil (MBbls)		Natural Gas (MMcf)		NGLs (MBbls)
Proved:
Developed		20,566		1,777,267		—
Undeveloped		13,553		1,632,475		—
Total Proved — 2013		34,119		3,409,742		—
Developed		28,481		2,245,004		9,118
Undeveloped		39,285		2,586,190		12,875
Total Proved — 2014		67,766		4,831,194		21,993
Developed		22,175		2,336,280		9,840
Undeveloped		—		—		—
Total Proved — 2015		22,175		2,336,280		9,840
Developed		21,475		2,321,613		9,903
Undeveloped		—		—		—
Total Proved — 2016		21,475		2,321,613		9,903

Standardized measure

	As of December 31,
	2016			2015			2014
Future cash inflows	$	5,812,234		$	6,312,095		$	27,331,391
Future production costs		(2,665,082	)		(3,006,265	)		(8,627,657	)
Future development costs		(355,923	)		(358,848	)		(3,859,385	)
Future income taxes		—			—			(3,898,355	)
Future net cash flows		2,791,229			2,946,982			10,945,994
Discount at 10%		(1,100,283	)		(1,081,333	)		(5,712,511	)
Standardized measure of discounted future net cash flows	$	1,690,946		$	1,865,649		$	5,233,483

Summary of changes in the standardized measure of discounted future net cash flows

	December 31,
	2016			2015			2014
Standardized measure, beginning	$	1,865,649		$	5,233,483		$	3,187,969
Net revisions of previous quantity estimates		(9,623	)		(2,126,998	)		(603,795	)
Extensions, discoveries and other changes		209,603			15,254			1,787,643
Sales of reserves in place		—			—			(398,506	)
Acquisition of reserves		—			—			2,552,491
Changes in future development costs		11,556			1,618,068			(1,013,652	)
Sales of oil and gas, net of production costs		(454,725	)		(550,879	)		(949,389	)
Net change in prices and production costs		(72,939	)		(6,996,416	)		1,010,052
Development costs incurred during the period that reduce    future development costs		22,523			548,112			342,987
Accretion of discount		186,565			709,736			413,177
Net changes in production rates and other		(67,663	)		1,551,413			(175,419	)
Net change in income taxes		—			1,863,876			(920,075	)
Aggregate changes		(174,703	)		(3,367,834	)		2,045,514
Standardized measure, ending	$	1,690,946		$	1,865,649		$	5,233,483

Costs incurred in oil and gas exploration and development activities

	Years Ended December 31,
	2016		2015		2014
United States
Property Acquisitions:
Unproved	$	983	$	13,845	$	26,106
Proved		—		—		895,179
Exploration*		224,277		18,164		197,664
Development		44,300		461,458		382,984
Total	$	269,560	$	493,467	$	1,501,933

* Exploration costs (as defined in Regulation S-X) includes costs spent on development of unproved reserves in the Pinedale Field.

Results of operations for oil and gas producing activities

F.    RESULTS OF OPERATIONS FOR OIL AND GAS PRODUCING ACTIVITIES:

	Years Ended December 31,
	2016			2015			2014
United States
Oil and gas revenue	$	721,091		$	839,111		$	1,230,020
Production expenses		(266,366	)		(288,231	)		(280,631	)
Depletion and depreciation		(125,121	)		(401,200	)		(292,951	)
Ceiling test and other impairments		—			(3,144,899	)		—
Income tax benefit (expense)		83,112			(9,841	)		3,736
Total	$	412,716		$	(3,005,060	)	$	660,174

Capitalized Costs Relating to Oil and Gas Producing Activities

G.    CAPITALIZED COSTS RELATING TO OIL AND GAS PRODUCING ACTIVITIES:

	December 31,
	2016			2015
Proven Properties:
Acquisition, equipment, exploration, drilling and    environmental costs	$	10,752,642		$	10,480,165
Less: accumulated depletion, depreciation and amortization		(9,742,176	)		(9,629,020	)
		1,010,466			851,145
Unproven Properties:
	$	1,010,466		$	851,145