Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Tax expense	$ 74	$ 163	$ 293	$ 382
Effective tax rate	4.00%	17.00%	11.30%	25.70%
Reduction in income tax expense	(88)		(45)
Interest and penalties		(41)
Income tax expense recognized for unrecognized tax benefits				0
Unrecognized tax benefits	$ 108		$ 108