Equity Method Investments (Detail) - The Company’s Equity in Earnings (Loss) of Joint Ventures (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Schedule of Equity Method Investments [Line Items]
Equity in earnings (loss) of joint ventures	$ 1,621		$ (91)		$ 7,287		$ (962)
ICP [Member]
Schedule of Equity Method Investments [Line Items]
Equity in earnings (loss) of joint ventures	1,604	[1]	(135)	[1]	7,192	[1]	(1,042)	[1]
DMI [Member]
Schedule of Equity Method Investments [Line Items]
Equity in earnings (loss) of joint ventures	$ 17		$ 44		$ 95		$ 80

[1] The cumulative effect of the change in estimate for the year to date period ended September 30, 2014 was a decrease in equity method investment earnings of $1,882, which reduced the joint venture investment earnings for the same period to 23.8 percent. The joint venture investment earnings for the quarter ended September 30, 2014 was 30 percent, as well as for the quarter and year to date periods ended September 30, 2013.