Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2016
Drilling Rigs and Other Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	1 year 3 months
Drilling Rigs and Other Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Buildings | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Buildings | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Other | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Other | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years