Commitments and Contingencies - Additional Information (Detail)			12 Months Ended
	Jun. 30, 2015 USD ($)	Aug. 02, 2013 USD ($)	Dec. 31, 2015 USD ($) MBbls	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Loss Contingencies [Line Items]
Lease of facilities, maturity year			2021
Payments related to lease obligations			$ 2,076,000	$ 966,000	$ 597,000
Contingent liability to surety insurance company			223,441,000
Commitments to use drilling rigs and acquisition of seismic data, value			$ 185,680,000
Commitments to use drilling rigs and acquisition of seismic data, period			3 years
Minimum barrels of oil spill to impose financial responsibility under Oil Pollution Act | MBbls			1,000
Minimum financial responsibility oil spill in specified state waters			$ 10,000,000
Minimum financial responsibility oil spill in continental shelf waters			35,000,000
Maximum financial responsibility in amounts if oil spill			150,000,000
Legal settlement		$ 18,373,000
Brokerage Fee Unpaid		1,119,000
Acquisition amount owed		$ 17,254,000
Litigation settlement amount	$ 2,119,000
Minimum potential range contingency loss	0		75,000
Maximum potential range contingency loss	2,119,000		$ 133,650
Second Claim [Member]
Loss Contingencies [Line Items]
Litigation settlement amount	$ 1,000,000