Annual report pursuant to Section 13 and 15(d)

Property Plant and Equipment (Detail)

v3.8.0.1
Property Plant and Equipment (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost $ 1,968,876 $ 2,014,083  
Less: Accumulated Depreciation and Amortization 1,343,105 1,320,644  
Property, Plant, and Equipment, Net 625,771 693,439  
Depreciation 119,600 136,300 $ 151,900
Other asset impairment charges 1,938 0 12,490
Gain (loss) on disposition of assets, net (2,851) (1,613) $ 1,643
Drilling Equipment      
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost 1,228,443 1,306,641  
Rental Tools      
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost 552,461 516,144  
Building, Land and Improvements      
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost 60,309 54,799  
Other      
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost 115,910 111,142  
Construction in Progress      
Property, Plant and Equipment [Line Items]      
Total Property, Plant and Equipment, at cost $ 11,753 $ 25,357