Supplemental Crude Oil and Natural Gas Information - Changes in Standardized Measure of Discounted Future Net Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Roll Forward]
Standardized measure of discounted future net cash flows at beginning of year	$ 10,470,177	$ 5,510,223	$ 6,476,284
Extensions, discoveries and improved recoveries, less related costs	5,162,635	1,462,629	786,587
Revisions of previous quantity estimates	(3,522,428)	(1,004,355)	(794,785)
Changes in estimated future development and abandonment costs	1,063,089	743,657	1,651,218
Sales of Minerals in Place	(9,192)	(41,077)	(90,390)
Net change in prices and production costs	4,224,473	3,808,116	(2,003,163)
Accretion of discount	1,183,347	665,507	798,597
Sales of crude oil and natural gas produced, net of production costs	(3,743,572)	(2,450,474)	(1,595,281)
Development costs incurred during the period	1,134,153	1,045,875	454,983
Change in timing of estimated future production and other	1,324,365	948,519	(538,665)
Change in income taxes	(1,602,230)	(218,443)	364,838
Net change	5,214,640	4,959,954	(966,061)
Standardized measure of discounted future net cash flows at end of year	$ 15,684,817	$ 10,470,177	$ 5,510,223