Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes Disclosure [Line Items]
Foreign tax credits	$ 0	$ 0	$ 5,019,000
Non-recognized benefit on foreign investments		2,980,000
Foreign tax assets valuation allowance	4,300,000	4,300,000
Claim of bonus tax depreciation		61,781,000	0	0
Uncertain tax positions	$ 153,000	$ 153,000