v2.4.0.8
Fair Value of Financial and Derivatives Instruments - Commodity Derivative Volumes and Prices (Detail)
Sep. 30, 2013
bbl
Crude Oil Basis Differential -2013 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 2,300
Contract Price 1.10
Crude Oil Basis Differential -2014 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 1,500
Contract Price 0.55
Propane - 2013 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 550
Contract Price 42.00
Propane - 2014 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 500
Contract Price 41.16
Natural Gasoline -2013 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 200
Contract Price 90.72
Natural Gasoline -2014 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 175
Contract Price 83.37
Natural Gas - 2013 Contract One [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 200,000
Contract Price 3.54
Natural Gas - 2013 Contract Two [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 190,000
Contract Price 3.80
Natural Gas Contracts [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 100,000
Natural Gas - 2014 [Member] | Swap [Member]
 
Derivative [Line Items]  
Volume Transacted 360,000
Contract Price 4.18
Crude Oil - 2013 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 650
Crude Oil - 2013 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 450
Crude Oil 2013 - Contract Three [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 1,200
Crude Oil - 2014 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 550
Crude Oil - 2014 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 950
Crude Oil -2015 [Member] | Collar [Member]
 
Derivative [Line Items]  
Volume Transacted 2,600
Minimum [Member] | Natural Gas Contracts [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 4.00
Minimum [Member] | Crude Oil - 2013 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 90.00
Minimum [Member] | Crude Oil - 2013 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 90.00
Minimum [Member] | Crude Oil 2013 - Contract Three [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 90.35
Minimum [Member] | Crude Oil - 2014 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 90.00
Minimum [Member] | Crude Oil - 2014 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 85.05
Minimum [Member] | Crude Oil -2015 [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 84.00
Maximum [Member] | Natural Gas Contracts [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 4.36
Maximum [Member] | Crude Oil - 2013 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 105.80
Maximum [Member] | Crude Oil - 2013 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 101.45
Maximum [Member] | Crude Oil 2013 - Contract Three [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 100.35
Maximum [Member] | Crude Oil - 2014 Contract One [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 105.50
Maximum [Member] | Crude Oil - 2014 Contract Two [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 95.05
Maximum [Member] | Crude Oil -2015 [Member] | Collar [Member]
 
Derivative [Line Items]  
Contract Price 91.00