Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017 USD ($) Counterparty	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest and dividends	$ 118,000	$ 136,000
Mark-to-market gain (loss)	1,500,000	259,000
Impairment on natural gas and oil properties	0	43,040,000
Allowance for doubtful accounts on accounts receivable	$ 5,558,000		$ 5,559,000
Number of financial institutions included in counter parties | Counterparty	22
Number of counterparties | Counterparty	5
Net derivative liability	$ 5,900,000
Western Oklahoma
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment on natural gas and oil properties	$ 0	$ 43,040,000