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Business Segments - Additional Information (Detail)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2020
USD ($)
Rigs
Sep. 30, 2020
USD ($)
Jun. 30, 2020
USD ($)
Mar. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2020
USD ($)
Rigs
Segment
Customer
Dec. 31, 2019
USD ($)
Customer
Dec. 31, 2018
USD ($)
Customer
Segment Reporting Disclosure [Line Items]                      
Number of reportable business segments | Segment                 3    
Impairment charge of drilling equipment     $ 8,300                
Total operating revenues $ 220,801 $ 207,141 250,380 $ 445,927 $ 492,297 $ 598,452 $ 675,765 $ 704,171 $ 1,124,249 $ 2,470,685 $ 3,326,997
Long-lived assets $ 2,761,041       3,306,677       $ 2,761,041 $ 3,306,677  
Major Customer                      
Segment Reporting Disclosure [Line Items]                      
Number of customers accounted for 10% or more of consolidated revenues | Customer                 0 0 0
Rigs and Spare Rig Components That Would No Longer Be Marketed                      
Segment Reporting Disclosure [Line Items]                      
Impairment charge of drilling equipment     $ 8,300             $ 173,000 $ 48,400
Contract Drilling                      
Segment Reporting Disclosure [Line Items]                      
Marketable land-based drilling rigs | Rigs 210               210    
Total operating revenues                 $ 669,126 1,308,350 1,430,492
Contract Drilling | Canada                      
Segment Reporting Disclosure [Line Items]                      
Total operating revenues                 1,000 4,700 $ 9,300
Long-lived assets $ 8,200       $ 20,100       $ 8,200 $ 20,100