Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes Disclosure [Line Items]
Federal Statutory rate	35.00%	35.00%	35.00%
Increase in total stake holders equity	$ 500,000
Operating loss carryforwards	143,400,000
Operating loss carryforwards, expiration date start	2022
Operating loss carryforwards, expiration date end	2032
Net operating loss carryforwards, majority expiration date start	2017
Net operating loss carryforwards, majority expiration date end	2027
Valuation allowance - state NOL carryforwards	219,000	541,000
Foreign tax credits	17,000,000
Foreign tax credits, expiration date start	2015
Foreign tax credits, expiration date end	2024
Valuation allowance - tax credit carryforwards	2,000,000
Valuation allowance - tax credit carryforwards recorded in 2014	100,000
Income taxes paid	9,590,000	1,161,000	237,000
Unrecognized tax benefits	0
State and Local Jurisdiction [Member]
Income Taxes Disclosure [Line Items]
Operating loss carryforwards	126,600,000
Operating loss carryforwards, expiration date end	2032
Valuation allowance - state NOL carryforwards	219,000
State and Local Jurisdiction [Member] | Valuation Allowance, Operating Loss Carryforwards [Member]
Income Taxes Disclosure [Line Items]
Reversal of valuation allowance	$ (300,000)