Annual report pursuant to Section 13 and 15(d)

Asset Impairment - Additional Information (Detail)

v2.4.0.8
Asset Impairment - Additional Information (Detail) (USD $)
 3 Months Ended 12 Months Ended
Dec. 31, 2013
rig
Dec. 31, 2011
Rigs
Dec. 31, 2013
rig
Dec. 31, 2012
Dec. 31, 2011
Rigs
Fair Value Inputs, Assets, Quantitative Information [Line Items]          
Number of rigs combined   2     2
Current estimated cost of rigs   $ 385,000,000     $ 385,000,000
Estimated total capitalized interest   50,700,000     50,700,000
Carrying value of rigs   339,500,000     339,500,000
Impairments and other charges   170,000,000 0 0 170,000,000
Asset Impairment charge after tax   109,100,000      
Fair value of rigs   169,500,000     169,500,000
Discounted rate of interests   10.00%      
Number of Land Rigs classification assets held for sale 2   5    
Impairment of property, plant and equipment     0 0 170,000,000
Number of rigs expected to be sold during the year     3    
Charge related to final settlement for a bankruptcy proceeding   1,400,000     1,400,000
Assets Held for Sale and Used [Member]
          
Fair Value Inputs, Assets, Quantitative Information [Line Items]          
Impairment of property, plant and equipment 1,900,000        
Assets Held for Sale and Used [Member] | Level 3 [Member]
          
Fair Value Inputs, Assets, Quantitative Information [Line Items]          
Impairment of property, plant and equipment $ 600,000