XML 90 R103.htm IDEA: XBRL DOCUMENT v2.4.1.9
Supplemental Information on Natural Gas and Oil Exploration, Development and Production Activities (Unaudited) - Capitalized Costs and Accumulated Depreciation, Depletion and Amortization (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Natural gas and oil properties:      
Properties subject to depletion $ 9,624,725us-gaap_CapitalizedCostsProvedProperties [1] $ 8,225,859us-gaap_CapitalizedCostsProvedProperties [1] $ 7,368,308us-gaap_CapitalizedCostsProvedProperties [1]
Unproved properties 943,246us-gaap_CapitalizedCostsUnprovedProperties [1] 807,022us-gaap_CapitalizedCostsUnprovedProperties [1] 743,467us-gaap_CapitalizedCostsUnprovedProperties [1]
Total 10,567,971us-gaap_OilAndGasPropertySuccessfulEffortMethodGross [1] 9,032,881us-gaap_OilAndGasPropertySuccessfulEffortMethodGross [1] 8,111,775us-gaap_OilAndGasPropertySuccessfulEffortMethodGross [1]
Accumulated depletion and depreciation (2,590,398)us-gaap_OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAndAmortization [1] (2,274,444)us-gaap_OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAndAmortization [1] (2,015,591)us-gaap_OilAndGasPropertySuccessfulEffortMethodAccumulatedDepreciationDepletionAndAmortization [1]
Natural gas and oil properties, successful efforts method, net $ 7,977,573us-gaap_OilAndGasPropertySuccessfulEffortMethodNet [1] $ 6,758,437us-gaap_OilAndGasPropertySuccessfulEffortMethodNet [1] $ 6,096,184us-gaap_OilAndGasPropertySuccessfulEffortMethodNet [1]
[1] Includes capitalized asset retirement costs and the associated accumulated amortization.