XML 41 R35.htm IDEA: XBRL DOCUMENT v2.4.0.6
Fair Value Measurements (Narrative) (Detail) (USD $)
Sep. 30, 2012
Dec. 31, 2011
Derivative liability, net $ 39,000 $ 300,000
Long-term debt 1,200,000,000 800,000,000
Long-term debt, fair value 1,276,000,000  
Asset retirement obligation, carrying value $ 20,807,000 $ 13,075,000