Summary of Significant Accounting Policies - Additional Information 2 (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Customer Counterparty	Dec. 31, 2015 USD ($) Customer	Dec. 31, 2014 Customer	Dec. 31, 2017 MMBTU / d bbl / d $ / Mcf $ / bbl
Summary Of Significant Accounting Policies [Line Items]
Allowance for doubtful accounts on accounts receivable	$ 5,559	$ 4,994
Number of customers accounted more than 10% of total oil and gas revenues | Customer	1	1	4
Net derivative asset	$ 16,800
Number of counterparties | Counterparty	5
Total Number of Derivative Counterparties | Counterparty	22
Accounting Standards Update 2016-09
Summary Of Significant Accounting Policies [Line Items]
Recognition of an excess tax deficiency in provision for income taxes rather than paid-in capital	$ 2,100
Cumulative-effect adjustments to retained earnings (deficit) and reduced deferred tax liability	$ 101,100
Natural Gas | Scenario Forecast | Counterparty One
Summary Of Significant Accounting Policies [Line Items]
Derivative contract volumes | MMBTU / d				6,575
Natural Gas | Minimum | Scenario Forecast | Counterparty One
Summary Of Significant Accounting Policies [Line Items]
Price used for calculating margin requirement | $ / Mcf				4.43
Crude Oil | Scenario Forecast | Counterparty One
Summary Of Significant Accounting Policies [Line Items]
Derivative contract volumes | bbl / d				608
Crude Oil | Minimum | Scenario Forecast | Counterparty One
Summary Of Significant Accounting Policies [Line Items]
Price used for calculating margin requirement | $ / bbl				83.20