Income Taxes - Components of Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 61,830	$ 47,245	$ 28,508
State and local	7,402	7,877	5,708
Total current expense (benefit)	69,232	55,122	34,216
Deferred:
Federal	(775)	(152)	7,917
State and local	82	(354)	(554)
Total deferred expense (benefit)	(693)	(506)	7,363
Income tax expense	$ 68,539	$ 54,616	$ 41,579