Provision for Income Taxes - Provision for Income Taxes (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
Disclosure - Provision for Income Taxes - Provision for Income Taxes (Detail) [Line Items]
Expected tax expense, at the U.S. federal statutory income tax rate of 35%			$ 2,541	$ 1,761
U.S. state income taxes and other, net			52	318
Total income tax expense	$ 1,015	$ 637	$ 2,593	$ 2,079