Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Environmental Compliance	Dec. 31, 2010 Legal Reserve	Dec. 31, 2013 Contract Drilling	Dec. 31, 2013 Maximum Firm Transportation	Dec. 31, 2013 Minimum Firm Transportation
Commitments and Contingencies Disclosure [Line Items]
Operating lease rental expense	$ 9,400,000	$ 11,000,000	$ 11,400,000
Contract term							15 years	1 year
Contract termination claims description						early termination provisions that would require us to pay penalties if we terminate the agreements prior to the end of their original terms.
Loss on contract termination for default						19,000,000
Reserve established for contingency matters					900,000
Suspense account	1,900,000
Asset retirement obligations	$ 6,437,000	$ 4,513,000	$ 6,283,000	$ 6,400,000