Property Dispositions - Additional Information (Detail) $ in Thousands	3 Months Ended																			12 Months Ended
	Dec. 31, 2018 USD ($)	[1]	Sep. 30, 2018 USD ($)	[1]	Jun. 30, 2018 USD ($)	[1]	Mar. 31, 2018 USD ($)	[1]	Dec. 31, 2017 USD ($)	[1]	Sep. 30, 2017 USD ($) a Boe		Jun. 30, 2017 USD ($)	[1]	Mar. 31, 2017 USD ($)	[1]	Dec. 31, 2016 USD ($) Boe	Sep. 30, 2016 a Boe	Jun. 30, 2016 USD ($) a	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 14, 2016 a
Property Acquisition And Dispositions [Line Items]
Proceeds from sale of assets																	$ 214,800			$ 54,458	$ 144,353	$ 631,549
Gain (Loss) on Disposition of Property Plant Equipment	$ 8,410		$ 1,510		$ 6,710		$ 41		$ 54,420		$ 3,562	[1]	$ 780		$ (3,638)					$ (16,671)	(55,124)	$ (304,489)
Proceeds from sale of non-producing leasehold																	295,600		$ 110,000
Gain (Loss) on disposition of non-producing leasehold																	$ 201,000		$ 96,900
STACK [Member]
Property Acquisition And Dispositions [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment																					63,500
Gain (Loss) on Disposition of Property Plant Equipment																					56,900
Arkoma Woodford [Member]
Property Acquisition And Dispositions [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment																					65,300
Land Subject to Ground Leases | a											26,000
Production, Barrels of Oil Equivalents | Boe											1,700
Gain (Loss) on disposition of non-producing leasehold																					(3,500)
OKLAHOMA
Property Acquisition And Dispositions [Line Items]
Proceeds from Sale of Oil and Gas Property and Equipment																					7,200
Gain (Loss) on disposition of oil loading facilities																					$ 4,200
SCOOP [Member]
Property Acquisition And Dispositions [Line Items]
Land Subject to Ground Leases | a																							30,000
Production, Barrels of Oil Equivalents | Boe																	700
WYOMING
Property Acquisition And Dispositions [Line Items]
Land Subject to Ground Leases | a																			132,000
NORTH DAKOTA
Property Acquisition And Dispositions [Line Items]
Land Subject to Ground Leases | a																		68,000
MONTANA
Property Acquisition And Dispositions [Line Items]
Land Subject to Ground Leases | a																		12,000
BAKKEN [Domain]
Property Acquisition And Dispositions [Line Items]
Production, Barrels of Oil Equivalents | Boe																		2,700

[1] Gains and losses on asset sales have been shown separately to illustrate the impact on quarterly results attributable to asset dispositions, which differ in significance from period to period and affect comparability. See Note 16. Property Dispositions for a discussion of notable dispositions.