XML 68 R72.htm IDEA: XBRL DOCUMENT v2.4.0.8
Derivative Activities - Additional Information (Detail) (USD $)
 12 Months Ended
Dec. 31, 2013
Institution
Counterparty
Feb. 28, 2013
Dec. 31, 2012
Dec. 31, 2011
Derivative [Line Items]        
Unrealized pre-tax derivative gain recorded in AOCI $ 10,200,000 $ 103,600,000    
Gains (Losses) in oil and gas sales related to settled hedging transactions 116,500,000   236,300,000 123,600,000
Gain (Loss) Recognized in Income (Ineffective Portion) (2,930,000)   1,125,000 9,544,000
Accumulated other comprehensive income, unrealized net gains, after tax balances, as March 1,2013   63,200,000    
Number of financial institutions with whom we conduct derivative activities 13      
Number of secured lenders not in banking credit facility 2      
2014
        
Derivative [Line Items]        
Unrealized pre-tax derivative gain expected to be reclassified into earnings 10,200,000      
Derivatives Excluding Basis Swaps
        
Derivative [Line Items]        
Derivative assets liabilities at fair value net 16,500,000      
Basis swaps
        
Derivative [Line Items]        
Derivative assets liabilities at fair value net $ 3,929,000      
Volume Hedged 320,280