Quarterly report pursuant to Section 13 or 15(d)

Reportable Segments - Additional Information (Detail)

v3.10.0.1
Reportable Segments - Additional Information (Detail)
 9 Months Ended
Sep. 30, 2018
segment
business_line
ft
Segment Information [Line Items]  
Number of business lines | business_line 2
Number of reportable segments 4
U.S. (Lower 48) Drilling  
Segment Information [Line Items]  
Number of business lines | business_line 2
Number of reportable segments 2
U.S. (Lower 48) Drilling | Minimum  
Segment Information [Line Items]  
Underwater drilling depth | ft 6
Drilling contract terms 20 days
U.S. (Lower 48) Drilling | Maximum  
Segment Information [Line Items]  
Underwater drilling depth | ft 12
Drilling contract terms 180 days
International & Alaska Drilling  
Segment Information [Line Items]  
Number of reportable segments 2
Drilling contract terms 1 year