Reportable Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017 segment
Segment Information [Line Items]
Number of Reportable Segments	4
Drilling Services [Member] | U.S. Operations [Member]
Segment Information [Line Items]
Number of Reportable Segments	2
Drilling Services [Member] | International Operations [Member]
Segment Information [Line Items]
Number of Reportable Segments	2
Rental Tools [Member] | U.S. Operations [Member]
Segment Information [Line Items]
Number of Reportable Segments	2
Rental Tools [Member] | International Operations [Member]
Segment Information [Line Items]
Number of Reportable Segments	2