Annual report pursuant to Section 13 and 15(d)

Assets Held for Sale - Additional Information (Detail)

v2.4.0.8
Assets Held for Sale - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2013
rig
Jun. 30, 2013
rig
Dec. 31, 2013
rig
Property, Plant and Equipment [Abstract]      
Number of Land Rigs classification assets held for sale 2   5
Number of Rigs Reclassified from Held-for-sale to Assets Held for Use and Inventory 2 3  
Depreciation expense on reclassified assets   $ 0.7  
Impairment of property, plant and equipment $ 1.9