Summary of Business and Basis of Presentation - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014
Summary of Business and Accounting Policies [Line Items]
Number of reporting segments			4
Number of natural gas producing wells and gas gathering assets			160
Antidilutive securities	322	1,012	14
Natural Gas Operations [Member]
Summary of Business and Accounting Policies [Line Items]
Annual distribution of natural gas			35,000,000,000
Marketing & Production Operations [Member]
Summary of Business and Accounting Policies [Line Items]
Natural gas customers			67,000
Annually market of natural gas			1,500,000,000
EWR Subsidiary [Member]
Summary of Business and Accounting Policies [Line Items]
Gross Percentage Of Working Interest			51.00%
Average Net Revenue Interest, Percentage			43.00%