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Description of Business and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Jan. 01, 2019
Basis Of Consolidation And Presentation [Line Items]            
Impairment charge of drilling equipment $ 8,300          
Reimbursement of workers compensation insurance claims included in other current assets     $ 36,100 $ 39,000    
Impairment expense related to oil and natural gas properties $ 604 $ 9,084 11,200 2,200 $ 1,000  
Right of use asset     16,850 31,275    
Operating lease liabilities     26,214      
Adjustment of loss before income tax     $ (931,018) (530,378) $ (367,408)  
Contract Drilling            
Basis Of Consolidation And Presentation [Line Items]            
Adjustment of loss before income tax       $ (6,600)    
Accounting Standards Update 2016-02            
Basis Of Consolidation And Presentation [Line Items]            
Right of use asset           $ 31,000
Operating lease liabilities           $ 35,800