Exploration expenses (including prospecting) related to oil and gas producing entities and would be included in operating expenses of that entity. Costs incurred in identifying areas that may warrant examination and in examining specific areas that are considered to have prospects of containing oil and gas reserves, including costs of drilling exploratory wells and exploratory-type stratigraphic test wells. Exploration costs may be incurred both before acquiring the related property (sometimes referred to in part as prospecting costs) and after acquiring the property. Principal types of exploration costs, which include depreciation and applicable operating costs of support equipment and facilities and other costs of exploration activities, are: (i) Costs of topographical, geographical and geophysical studies, rights of access to properties to conduct those studies, and salaries and other expenses of geologists, geophysical crews, and others conducting those studies. Collectively, these are sometimes referred to as geological and geophysical or "G&G" costs. (ii) Costs of carrying and retaining undeveloped properties, such as delay rentals, ad valorem taxes on properties, legal costs for title defense, and the maintenance of land and lease records. (iii) Dry hole contributions and bottom hole contributions. (iv) Costs of drilling and equipping exploratory wells. (v) Costs of drilling exploratory-type stratigraphic test wells.

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Supplemental Oil and Gas Disclosures - Unaudited - Results of Operations for Oil and Natural Gas Producing Activities (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Revenues	$ 483,864	$ 482,743	$ 529,405	$ 575,732	$ 599,755	$ 674,629	$ 573,751	$ 473,812	$ 2,071,744	$ 2,321,947	$ 1,293,719
Production costs									464,782	434,801	321,007
Depreciation, depletion and amortization									759,900	613,928	515,600
Exploration expenses									6,658	27,432	11,600
Impairment									5,389	384,228	6,887
Income tax expense									40,745	30,770	67,148
Results of operations for crude oil and natural gas producing activities									130,913	98,865	112,392
Oil and gas
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Revenues									$ 1,408,771	$ 1,590,024	$ 1,034,634