Equity Method Investments - Additional Information (Details)	Sep. 30, 2016	Dec. 31, 2015
Mars
Schedule of Equity Method Investments [Line Items]
Equity method investment percentage	28.60%	28.60%
Bengal
Schedule of Equity Method Investments [Line Items]
Equity method investment percentage	50.00%	49.00%
Poseidon
Schedule of Equity Method Investments [Line Items]
Equity method investment percentage	36.00%	36.00%