Equity Method Investments - The Company's Equity in Earnings (Loss) of Joint Ventures (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)	$ 92	$ 1,562	$ 3,096	$ 1,352	$ 2,850	$ 1,621	$ 2,331	$ 3,335	$ 6,102	$ 10,137	$ (204)
ICP (30% interest) [Member]
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)									6,242	10,098	(251)
DMI (50% interest) [Member]
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)									$ (140)	$ 39	$ 47