Acquisitions and Dispositions - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	0 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Miscallaneous Proved Property	Apr. 30, 2013 Delaware and Permian Basin	Jun. 30, 2013 Miscellaneous Proved and Unproved Properties	Jun. 30, 2014 Nora Gathering, LLC	Jun. 30, 2014 Nora Gathering, LLC	Jun. 30, 2014 Conger Exchange Transaction	Apr. 30, 2014 Conger Exchange Transaction	Apr. 30, 2014 Conger Exchange Transaction EQT Corporation	Jun. 30, 2014 Conger Exchange Transaction EQT Corporation	Jun. 30, 2014 Conger Exchange Transaction EQT Corporation
Significant Acquisitions And Disposals [Line Items]
Cash proceeds from sale of assets										$ 145,000,000		$ 145,000,000
Sale and exchange transaction, closing date														Jun. 16, 2014
Gain (loss) on sale of assets	282,064,000	83,287,000	281,711,000	83,121,000	1,600,000	83,300,000	3,700,000	10,000,000	10,000,000			275,200,000
Selling expenses for property sale						4,200,000							5,000,000	5,000,000
Carrying amount of assets prior to exchange											271,800,000
Percentage of ownership interest, acquired								50.00%	50.00%
Percentage of ownership interest with Company								50.00%	50.00%
Trade receivables relating to acquisition								5,546,000	5,546,000
Recognized revenue from sale of property interests acquired										2,800,000
Net operating income										2,100,000
Proceeds from sale of oil and gas					$ 1,100,000	$ 275,000,000	$ 25,200,000