Provision for Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Expected tax expense, at the U.S. federal statutory income tax rate of 35%			$ 2,500	$ 2,808
Domestic production activities deduction			(218)	(260)
State income taxes			208	238
Other, net			15	13
Total income tax expense	$ 1,320	$ 1,504	$ 2,505	$ 2,799