Fair Value Measurements - Additional Information (Detail)	3 Months Ended					12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest and dividends						$ 1,100,000	$ 1,100,000	$ 4,100,000
Mark-to-market gain (loss)						8,500,000	$ (7,900,000)	4,200,000
Deficiency charges	$ 14,000,000.0
Closing stock price | $ / shares		$ 9.57					$ 9.57
Impairment of goodwill		$ 1,641,197,000	$ 0	$ 0	$ 0	$ 0	$ 1,641,197,000	0
Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Annual discount rate	12					12
North Louisiana
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment on natural gas and oil properties	$ 1,100,000,000
Pennsylvania
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets, fair value		$ 0					0
Oklahoma
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment on natural gas and oil properties					$ 7,300,000		$ 15,300,000
Oklahoma And Texas Panhandle
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment on natural gas and oil properties								$ 63,700,000