Investment in Unconsolidated Affiliate - Schedule of Estimated Aggregate Amortization of Premium (Detail) - Gulf LNG Holdings Group, LLC Acquisition [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($)
Schedule Of Equity Method Investments [Line Items]
Estimated future amortization expense, 2016	$ 309
Estimated future amortization expense, 2017	309
Estimated future amortization expense, 2018	309
Estimated future amortization expense, 2019	309
Estimated future amortization expense, 2020	309
Estimated future amortization expense, Thereafter	6,444
Total future amortization expense	$ 7,989