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Derivatives - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mississippian Trust I
  
Derivative Instruments and Hedging Activities Disclosure [Line Items]  
Derivative agreement effective date Apr. 01, 2011
Commodity derivative contracts covering volumes of oil and gas production, date Dec. 31, 2015
Permian Trust
  
Derivative Instruments and Hedging Activities Disclosure [Line Items]  
Derivative agreement effective date Aug. 01, 2011
Commodity derivative contracts covering volumes of oil and gas production, date Mar. 31, 2015
Mississippian Trust II
  
Derivative Instruments and Hedging Activities Disclosure [Line Items]  
Derivative agreement effective date Apr. 01, 2012
Commodity derivative contracts covering volumes of oil and gas production, date Dec. 31, 2014
Interest rate swap
  
Derivative Instruments and Hedging Activities Disclosure [Line Items]  
Contract period end Apr. 01, 2013
Senior Floating Rate Notes due 2014 | Fixed To Floating Interest Rate Swap Through April 1st 2013
  
Derivative Instruments and Hedging Activities Disclosure [Line Items]  
Notional amount of interest rate derivatives 350.0
Derivative, fixed interest rate 6.69%