Equity Method Investments (Detail) - The Company’s Equity in Earnings (Loss) of Joint Ventures (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)	$ 2,850	$ 1,621	$ 2,331	$ 3,335	$ 758	$ (91)	$ 71	$ (942)	$ 10,137	$ (204)
ICP (30% interest) [Member]
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)									10,098	(251)
DMI (50% interest) [Member]
Schedule of Equity Method Investments [Line Items]
Equity In earnings (loss)									$ 39	$ 47