Supplemental Crude Oil and Natural Gas Information - Schedule of Proved Crude Oil and Natural Gas Reserves (Detail)	12 Months Ended
	Dec. 31, 2019 MBoe MMcf MBbls	Dec. 31, 2018 MBoe MMcf MBbls	Dec. 31, 2017 MBoe MMcf MBbls	Dec. 31, 2016 MBoe
Reserve Quantities [Line Items]
Proved Developed and Undeveloped Reserve, Net (Energy) | MBoe	1,619,265	1,522,365	1,330,995	1,274,864
Changes in Proved Reserves [Roll Forward]
Revisions of previous estimates | MBoe	(148,848)	(269,253)	(82,012)
Extensions, discoveries, and other additions | MBoe	365,034	565,030	240,206
Proved Developed and Undeveloped Reserve, Production (Energy) | MBoe	124,244	108,839	88,562
Sales of minerals in place, Total | MBoe	(1,840)	(8,011)	(15,197)
Purchases of minerals in place, Total | MBoe	6,798	12,443	1,696
Percent of proved crude oil reserve estimates prepared by external reserve engineers	91.00%	98.00%	96.00%
Natural Gas [Member]
Changes in Proved Reserves [Roll Forward]
Proved reserves at beginning of period | MMcf	4,591,614	4,140,281	3,789,818
Revisions of previous estimates | MMcf	(363,239)	(1,153,555)	(25,390)
Extensions, discoveries and other additions | MMcf	1,213,947	1,871,777	661,867
Production | MMcf	(311,865)	(284,730)	(228,159)
Sales of minerals in place | MMcf	(6,224)	(35,142)	(64,989)
Purchases of minerals in place | MMcf	30,238	52,983	7,134
Proved reserves at end of period | MMcf	5,154,471	4,591,614	4,140,281
Crude Oil [Member]
Changes in Proved Reserves [Roll Forward]
Proved reserves at beginning of period | MBbls	757,096	640,949	643,228
Revisions of previous estimates | MBbls	(88,307)	(76,994)	(77,779)
Extensions, discoveries and other additions | MBbls	162,710	253,066	129,895
Production | MBbls	(72,267)	(61,384)	(50,536)
Sales of minerals in place | MBbls	(803)	(2,154)	(4,365)
Purchases of minerals in place | MBbls	1,758	3,613	506
Proved reserves at end of period | MBbls	760,187	757,096	640,949