Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) bbl / d Mcf / d	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Commitments And Contingencies Disclosure [Line Items]
Rent expense under operating leases | $	$ 14.0	$ 15.9	$ 13.3
Minimum remaining terms of leases on undeveloped acreage, in years	3 years
Maximum remaining terms of leases on undeveloped acreage, in years	5 years
2018
Commitments And Contingencies Disclosure [Line Items]
Delivery commitments contingent upon pipeline construction or modification per day | bbl / d	10,000
Minimum
Commitments And Contingencies Disclosure [Line Items]
Transportation and gathering commitments contingent upon pipeline construction or modification, term of contract	15 years
Maximum
Commitments And Contingencies Disclosure [Line Items]
Transportation and gathering commitments contingent upon pipeline construction or modification, term of contract	20 years
Natural Gas | 2032
Commitments And Contingencies Disclosure [Line Items]
Transportation commitments contingent upon pipeline construction or modification	1,300,000
Natural Gas | 2037
Commitments And Contingencies Disclosure [Line Items]
Transportation commitments contingent upon pipeline construction or modification	400,000
Natural Gas | 2017 through 2032
Commitments And Contingencies Disclosure [Line Items]
Gathering commitments contingent upon pipeline construction or modification	400,000
Natural Gas | 2018
Commitments And Contingencies Disclosure [Line Items]
Delivery commitments contingent upon pipeline construction or modification per day	65,000
Natural Gas | 2017
Commitments And Contingencies Disclosure [Line Items]
Delivery commitments contingent upon pipeline construction or modification per day	50,000
Natural Gas | 2019
Commitments And Contingencies Disclosure [Line Items]
Delivery commitments contingent upon pipeline construction or modification per day	215,000
North Louisiana
Commitments And Contingencies Disclosure [Line Items]
Liability for expected volume deficiency payments | $	$ 59.2