Annual report pursuant to Section 13 and 15(d)

Reconciliation of Asset Retirement Obligations Liability (Detail)

v2.4.0.8
Reconciliation of Asset Retirement Obligations Liability (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Asset retirement obligations, beginning of period $ 384,053 $ 393,880  
Liabilities settled (81,543) (112,827)  
Accretion of discount 20,918 20,055 29,771
Disposition of properties (19,564) (3,993)  
Liabilities assumed through acquisition 4,233 31,664  
Liabilities incurred 1,745 1,815  
Asset retirement obligations, end of period 354,422 384,053 393,880
Less current portion 77,785 92,630  
Long-term 276,637 291,423  
Hurricane Ike
     
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Revisions of estimated liabilities 6,801 (20,616)  
All Other
     
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]      
Revisions of estimated liabilities $ 37,779 $ 74,075