XML 78 R77.htm IDEA: XBRL DOCUMENT v2.4.0.8
Derivatives - Cash Settlements and Valuation Gains and Losses on Commodity Derivative Contracts and Interest Rate Swaps (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Derivative Instruments, (Gain) Loss        
Loss (gain) due to change in fair value     $ 56,085 $ (234,705)
Loss (gain) on derivative contracts 132,808 193,497 70,051 (221,707)
Commodity Derivatives
        
Derivative Instruments, (Gain) Loss        
Loss (gain) on settlement 13,203 [1] (28,970) [1] 11,571 [1] 7,366 [1]
Loss (gain) due to change in fair value 119,605 222,467 58,480 (229,073)
Loss (gain) on derivative contracts 132,808 193,497 70,051 (221,707)
Interest Rate Swap
        
Derivative Instruments, (Gain) Loss        
Loss (gain) on settlement 0 2,330 2,409 6,824
Loss (gain) due to change in fair value 0 (2,033) (2,395) (5,632)
Loss (gain) on derivative contracts $ 0 $ 297 $ 14 $ 1,192
[1] The three-month period ended September 30, 2012 included $2.1 million of gains related to settlements of commodity derivative contracts with contractual maturities after the quarterly period in which they were settled (“early settlements”). The nine-month periods ended September 30, 2013 and 2012 included $29.3 million and $(59.5) million, respectively, of losses (gains) related to early settlements. The nine-month period ended September 30, 2012 also included $117.1 million of non-cash losses due to the amendment of derivative contracts in January 2012.