Equity Method Investments - The Company's Investment in Joint Ventures (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 18,427	$ 12,373
ICP [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	18,043	11,924
DMI [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 384	$ 449