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Equity Method Investments - Additional Information (Detail) (USD $)
 1 Months Ended 12 Months Ended
Sep. 30, 2013
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2006
Schedule Of Equity Method Investments [Line Items]          
Losses (Income) from equity method investments, net of distributions   $ 2,973,000 $ (5,670,000) $ (16,871,000)  
Equity method investments   129,034,000 132,449,000    
Whipstock Natural Gas Services Llc
          
Schedule Of Equity Method Investments [Line Items]          
Percentage ownership interest   50.00%     50.00%
Cash contributed for investment         11,700,000
Losses (Income) from equity method investments, net of distributions   608,000 818,000 481,000  
Reduction in equity to eliminate the profit on services provided     14,000 6,000  
Proceeds from sale of equity method investments 7,000,000        
Equity method investment, Realized gain (loss) on disposal 4,400,000        
Nora Gathering, LLC
          
Schedule Of Equity Method Investments [Line Items]          
Percentage ownership interest   50.00%      
Cash contributed for investment   94,700,000      
Losses (Income) from equity method investments, net of distributions   146,000 1,200,000 563,000  
Equity method investments   129,000,000      
Cash distribution from investment   9,000,000 12,800,000 23,500,000  
Reduction in equity to eliminate the profit from gathering and transportation fees   $ 7,700,000 $ 7,500,000 $ 7,700,000