Income Taxes - Component of Income Taxes (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Line Items]
Expected tax provision (benefit) at U.S. federal statutory income tax rate of 35%	$ 1,800,000	$ (5,200,000)
Incremental U.S. tax and rate differences on equity in earnings	(1,000,000)	(7,400,000)
Nontaxable income	(300,000)	(200,000)
U.S. state income taxes and other, net	500,000	100,000
Total	$ 970,000	$ (12,658,000)