Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Income Tax Disclosure [Abstract]
Effective tax rate	25.50%	30.70%	25.80%	31.50%
Accrued interest	$ 800,000		$ 800,000
Accrued penalties	$ 0		$ 0