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 Taxes [Line Items]
Provision (benefit) for income taxes	$ 278	$ 5,983	$ 433	$ 865
Effective income tax rate	0.75%	16.40%	1.16%	5.60%
Discrete tax benefits | Reduction of Uncertain Tax Positions
Income Taxes [Line Items]
Provision (benefit) for income taxes			$ (1,400)	$ (1,000)