Income Taxes - Reconciliation of Differences between Income Tax Provision and Income Tax Determined by Applying US Federal Statutory Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Amount [Abstract]
U.S. Federal statutory taxes	$ 37,141	$ 49,671	$ 35,990
State and local taxes, net of U.S. Federal benefit	7,716	5,110	3,747
Permanent items	470	576	396
Excess tax benefits from vesting or settlement of stock compensation awards	(2,368)	(1,454)	(1,749)
Domestic production activities deduction		(4,376)	(2,740)
Federal credits	(662)	(534)	(488)
Other	(8)	(2,202)	(173)
Total income tax provision	$ 42,289	$ 46,791	$ 34,983