Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Lenders Company	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2013 Surface Property Fair Value, Measurements, Nonrecurring	Jun. 30, 2013 Surface Property Fair Value, Measurements, Nonrecurring	Dec. 31, 2013 Surface Property Fair Value, Measurements, Nonrecurring	Jun. 30, 2014 Basis Swaps Fair Value, Inputs, Level 3 Swaps
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of natural gas basis swap									4
Interest and dividends	$ 103,000	$ 629,000	$ 171,000	$ 668,000
Mark-to-market gain (loss)	2,100,000	(1,000,000)	2,600,000	586,000
Impairment on oil and gas properties	25,000,000		25,000,000
Impairment	24,991,000	741,000	24,991,000	741,000		741,000	741,000	741,000
Allowance for uncollectible receivables	2,700,000		2,700,000		2,500,000
Number of financial institutions included in counter parties			15
Number of secured lenders not in banking credit facility			2
Net derivative liabilities	$ 2,300,000		$ 2,300,000