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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Line Items]      
Increase in goodwill $ 2,104,000    
Amortization expense on intangible assets 3,700,000 $ 5,400,000  
Contract Drilling      
Goodwill And Intangible Assets Disclosure [Line Items]      
Accumulated impairment losses 0   $ 0
Other Operations      
Goodwill And Intangible Assets Disclosure [Line Items]      
Increase in goodwill 2,104,000    
Accumulated impairment losses $ 0   $ 0