Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Effective tax rate	33.20%	34.40%	28.20%	32.60%
Accrued uncertain tax benefits	$ 1,800,000		$ 1,800,000
Accrued interest	900,000		900,000
Accrued penalties	$ 0		$ 0