Income Before Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments [Abstract]
Domestic source	$ 82,033	$ 59,705	$ 43,069
Foreign source	1,819	2,224	1,915
Income before provision for income taxes	$ 83,852	$ 61,929	$ 44,984