Income Taxes - Summary of Income Tax Provision Reconciled to Income Taxes that Computed at Statutory Federal Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Federal income tax, at statutory rates	$ 16,861	$ 28,017	$ 21,994
Increase (deduction) in taxes resulting from:
Tax-exempt income	(1,096)	(1,652)	(1,671)
Excise tax on real estate investment trust (REIT) dividend	0	1,945	0
Adjustment to net deferred tax asset for Tax Cuts and Jobs Act	0	(1,343)	0
State income tax, net of federal income tax effect	1,880	931	552
Adjustment to net deferred tax asset for change in NJ tax law	(943)	0	0
Excess tax benefits from employee share-based payments	(318)	(587)	0
Other, net	504	158	446
Total provision for income taxes	$ 16,888	$ 27,469	$ 21,321