Annual report pursuant to Section 13 and 15(d)

Summary of Property and Equipment (Detail)

v3.20.4
Summary of Property and Equipment (Detail)
3 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2020
USD ($)
$ / bbl
Sep. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
$ / bbl
Dec. 31, 2019
USD ($)
$ / bbl
Dec. 31, 2018
USD ($)
$ / bbl
Dec. 31, 2017
USD ($)
Property, Plant and Equipment [Abstract]            
Proved Oil and Gas Property, Full Cost Method $ 1,545,910,000   $ 1,545,910,000 $ 1,409,219,000    
Undeveloped Leasehold Costs Transferred     8,300,000 16,800,000    
Interest Costs Capitalized     $ 2,700,000 $ 4,100,000 $ 9,100,000  
Amortization Expense Per Physical Unit of Production | $ / bbl 15.83   15.83 17.25 16.11  
Unproved Oil and Gas Property excluded $ 49,900,000   $ 49,900,000 $ 53,200,000    
Wells-in-progress 1,200,000   1,200,000      
Asset Impairment Charges 120,300,000 $ 271,500,000 391,849,000 0 $ 0  
Capitalized Costs of Unproved Properties Excluded from Amortization, Cumulative 2,200,000   2,200,000 1,600,000 2,000,000.0 $ 44,200,000
Capitalized Interest Remaining 1,100,000   1,100,000      
Capitalized Costs, Proved Properties 2,100,000   2,100,000 4,100,000 $ 3,700,000  
Oil and gas properties:            
Unproved Oil and Gas Property, Full Cost Method 49,935,000   49,935,000 53,200,000    
Oil and Gas Property, Full Cost Method, Gross 1,595,845,000   1,595,845,000 1,462,419,000    
Other property and equipment 27,746,000   27,746,000 25,915,000    
Total property and equipment 1,623,591,000   1,623,591,000 1,488,334,000    
Accumulated depreciation, depletion and amortization (900,042,000)   (900,042,000) (367,909,000)    
Property and equipment, net (successful efforts method) $ 723,549,000   $ 723,549,000 $ 1,120,425,000