SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Oil and Gas Reserve Information (Detail) MBoe in Thousands	12 Months Ended
	Dec. 31, 2018 MBoe MMcf MBbls	Dec. 31, 2017 MBoe MMcf MBbls	Dec. 31, 2016 MBoe MMcf MBbls	Dec. 31, 2015 MBoe MMcf MBbls
Reserve Quantities [Line Items]
Proved developed reserves	1,081,316	1,023,663	1,173,635	1,331,397
Proved undeveloped reserves	153,081	151,323	137,616	232,336
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	1,174,986	1,311,251	1,563,733
Extensions, discoveries and other additions	302,509	229,977	103,204
Purchases of minerals in-place	331	2,285	1,580
Revisions of previous estimates	(73,319)	10,394	(159,341)
Production	(170,051)	(166,923)	(190,942)
Sales of minerals in-place	(59)	(211,998)	(6,983)
Ending balance	1,234,397	1,174,986	1,311,251
United States
Reserve Quantities [Line Items]
Proved developed reserves	769,125	699,786	656,087	726,424
Proved undeveloped reserves	123,493	111,001	76,950	120,210
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	810,787	733,037	846,634
Extensions, discoveries and other additions	240,322	145,322	56,458
Purchases of minerals in-place	331	991	24
Revisions of previous estimates	(63,451)	12,903	(87,954)
Production	(95,312)	(75,151)	(81,994)
Sales of minerals in-place	(59)	(6,315)	(131)
Ending balance	892,618	810,787	733,037
Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	157,662	209,647
Proved undeveloped reserves	0	0	17,931	70,300
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	175,593	279,947
Extensions, discoveries and other additions	0	24,115	9,166
Purchases of minerals in-place	0	1,294	0
Revisions of previous estimates	0	16,136	(84,984)
Production	0	(11,455)	(21,684)
Sales of minerals in-place	0	(205,683)	(6,852)
Ending balance	0	0	175,593
Egypt
Reserve Quantities [Line Items]
Proved developed reserves	189,871	215,364	252,630	275,033
Proved undeveloped reserves	15,045	24,112	27,336	26,929
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	239,476	279,966	301,962
Extensions, discoveries and other additions	35,849	40,731	23,674
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	(16,007)	(21,936)	16,599
Production	(54,402)	(59,285)	(62,269)
Sales of minerals in-place	0	0	0
Ending balance	204,916	239,476	279,966
North Sea
Reserve Quantities [Line Items]
Proved developed reserves	122,320	108,513	107,256	120,293
Proved undeveloped reserves	14,543	16,210	15,399	14,897
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	124,723	122,655	135,190
Extensions, discoveries and other additions	26,338	19,809	13,906
Purchases of minerals in-place	0	0	1,556
Revisions of previous estimates	6,139	3,291	(3,002)
Production	(20,337)	(21,032)	(24,995)
Sales of minerals in-place	0	0	0
Ending balance	136,863	124,723	122,655
Crude Oil and Condensate
Reserve Quantities [Line Items]
Proved developed reserves	514,989	521,445	582,317	665,063
Proved undeveloped reserves	65,944	62,115	59,965	127,996
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	583,560	642,282	793,059
Extensions, discoveries and other additions	100,131	105,579	40,351
Purchases of minerals in-place	140	421	459
Revisions of previous estimates	(13,277)	(675)	(88,714)
Production	(89,574)	(89,156)	(100,744)
Sales of minerals in-place	(47)	(74,891)	(2,129)
Ending balance	580,933	583,560	642,282
Crude Oil and Condensate | United States
Reserve Quantities [Line Items]
Proved developed reserves	300,484	304,279	300,900	348,797
Proved undeveloped reserves	45,182	31,904	21,088	60,505
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	336,183	321,988	409,302
Extensions, discoveries and other additions	61,976	48,391	9,614
Purchases of minerals in-place	140	46	21
Revisions of previous estimates	(14,334)	825	(58,882)
Production	(38,252)	(33,394)	(38,000)
Sales of minerals in-place	(47)	(1,673)	(67)
Ending balance	345,666	336,183	321,988
Crude Oil and Condensate | Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	51,508	67,847
Proved undeveloped reserves	0	0	7,906	38,326
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	59,414	106,173
Extensions, discoveries and other additions	0	14,025	3,372
Purchases of minerals in-place	0	375	0
Revisions of previous estimates	0	1,829	(43,282)
Production	0	(2,425)	(4,787)
Sales of minerals in-place	0	(73,218)	(2,062)
Ending balance	0	0	59,414
Crude Oil and Condensate | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	110,014	124,568	138,771	144,164
Proved undeveloped reserves	9,484	16,198	20,187	17,856
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	140,766	158,958	162,020
Extensions, discoveries and other additions	22,473	27,140	17,599
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	(9,556)	(9,839)	17,301
Production	(34,185)	(35,493)	(37,962)
Sales of minerals in-place	0	0	0
Ending balance	119,498	140,766	158,958
Crude Oil and Condensate | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	104,491	92,598	91,138	104,255
Proved undeveloped reserves	11,278	14,013	10,784	11,309
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	106,611	101,922	115,564
Extensions, discoveries and other additions	15,682	16,023	9,766
Purchases of minerals in-place	0	0	438
Revisions of previous estimates	10,613	6,510	(3,851)
Production	(17,137)	(17,844)	(19,995)
Sales of minerals in-place	0	0	0
Ending balance	115,769	106,611	101,922
Natural Gas Liquids
Reserve Quantities [Line Items]
Proved developed reserves	200,014	173,715	171,883	168,786
Proved undeveloped reserves	34,487	29,951	20,561	30,151
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	203,666	192,444	198,937
Extensions, discoveries and other additions	62,578	36,495	11,872
Purchases of minerals in-place	40	405	7
Revisions of previous estimates	(10,038)	11,176	5,627
Production	(21,740)	(19,515)	(22,942)
Sales of minerals in-place	(5)	(17,339)	(1,057)
Ending balance	234,501	203,666	192,444
Natural Gas Liquids | United States
Reserve Quantities [Line Items]
Proved developed reserves	197,574	171,005	155,124	150,265
Proved undeveloped reserves	33,796	29,559	17,311	24,939
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	200,564	172,435	175,204
Extensions, discoveries and other additions	60,990	33,806	10,238
Purchases of minerals in-place	40	206	2
Revisions of previous estimates	(9,250)	12,982	6,824
Production	(20,969)	(17,766)	(19,824)
Sales of minerals in-place	(5)	(1,099)	(9)
Ending balance	231,370	200,564	172,435
Natural Gas Liquids | Canada
Reserve Quantities [Line Items]
Proved developed reserves	0	0	13,866	15,246
Proved undeveloped reserves	0	0	2,473	4,839
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	0	16,339	20,085
Extensions, discoveries and other additions	0	1,794	755
Purchases of minerals in-place	0	199	0
Revisions of previous estimates	0	(1,060)	(1,355)
Production	0	(1,032)	(2,098)
Sales of minerals in-place	0	(16,240)	(1,048)
Ending balance	0	0	16,339
Natural Gas Liquids | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	502	685	1,266	1,491
Proved undeveloped reserves	60	39	131	78
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	724	1,397	1,569
Extensions, discoveries and other additions	144	50	208
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	31	(425)	17
Production	(337)	(298)	(397)
Sales of minerals in-place	0	0	0
Ending balance	562	724	1,397
Natural Gas Liquids | North Sea
Reserve Quantities [Line Items]
Proved developed reserves	1,938	2,025	1,627	1,784
Proved undeveloped reserves	631	353	646	295
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance	2,378	2,273	2,079
Extensions, discoveries and other additions	1,444	845	671
Purchases of minerals in-place	0	0	5
Revisions of previous estimates	(819)	(321)	141
Production	(434)	(419)	(623)
Sales of minerals in-place	0	0	0
Ending balance	2,569	2,378	2,273
Natural Gas
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	2,197,882	1,971,018	2,516,610	2,985,290
Proved undeveloped reserves | MMcf	315,900	355,544	342,538	445,132
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	2,326,562	2,859,148	3,430,422
Extensions, discoveries and other additions | MMcf	838,803	527,418	305,883
Purchases of minerals in-place | MMcf	906	8,753	6,684
Revisions of previous estimates | MMcf	(300,029)	(641)	(457,524)
Production | MMcf	(352,419)	(349,509)	(403,533)
Sales of minerals in-place | MMcf	(41)	(718,607)	(22,784)
Ending balance | MMcf	2,513,782	2,326,562	2,859,148
Natural Gas | United States
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	1,626,403	1,347,009	1,200,379	1,364,174
Proved undeveloped reserves | MMcf	267,090	297,226	231,304	208,594
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	1,644,235	1,431,683	1,572,768
Extensions, discoveries and other additions | MMcf	704,135	378,747	219,633
Purchases of minerals in-place | MMcf	906	4,434	7
Revisions of previous estimates | MMcf	(239,204)	(5,431)	(215,378)
Production | MMcf	(216,538)	(143,943)	(145,019)
Sales of minerals in-place | MMcf	(41)	(21,255)	(328)
Ending balance | MMcf	1,893,493	1,644,235	1,431,683
Natural Gas | Canada
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	0	0	553,724	759,321
Proved undeveloped reserves | MMcf	0	0	45,312	162,809
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	0	599,036	922,130
Extensions, discoveries and other additions | MMcf	0	49,780	30,234
Purchases of minerals in-place	0	4,319	0
Revisions of previous estimates	0	92,207	(242,080)
Production	0	(47,990)	(88,792)
Sales of minerals in-place	0	(697,352)	(22,456)
Ending balance | MMcf	0	0	599,036
Natural Gas | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	476,132	540,667	675,559	776,263
Proved undeveloped reserves | MMcf	33,006	47,255	42,109	53,969
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	587,922	717,668	830,232
Extensions, discoveries and other additions | MMcf	79,394	81,245	35,202
Purchases of minerals in-place	0	0	0
Revisions of previous estimates	(38,892)	(70,030)	(4,305)
Production	(119,286)	(140,961)	(143,461)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	509,138	587,922	717,668
Natural Gas | North Sea
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	95,347	83,342	86,948	85,532
Proved undeveloped reserves | MMcf	15,804	11,063	23,813	19,760
Proved Developed and Undeveloped Reserves [Roll Forward]
Beginning balance | MMcf	94,405	110,761	105,292
Extensions, discoveries and other additions | MMcf	55,274	17,646	20,814
Purchases of minerals in-place	0	0	6,677
Revisions of previous estimates	(21,933)	(17,387)	4,239
Production	(16,595)	(16,615)	(26,261)
Sales of minerals in-place	0	0	0
Ending balance | MMcf	111,151	94,405	110,761
Noncontrolling Interest | Egypt
Proved Developed and Undeveloped Reserves [Roll Forward]
Proved developed reserves (Energy) | MBoe	68	80	93	101
Noncontrolling Interest | Crude Oil and Condensate | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	40,000	47,000	53,000	54,000
Noncontrolling Interest | Natural Gas Liquids | Egypt
Reserve Quantities [Line Items]
Proved developed reserves	187	241	466	523
Noncontrolling Interest | Natural Gas | Egypt
Reserve Quantities [Line Items]
Proved developed reserves | MMcf	170,000	196,000	239,000	277,000