Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Schedule Of Pre Tax Income [Line Items]
Excess tax benefits on share based payments	$ 3.0	$ 1.8
New York State [Member] | Earliest Tax Year [Member]
Schedule Of Pre Tax Income [Line Items]
Income tax year under examination	2010
New York State [Member] | Latest Tax Year [Member]
Schedule Of Pre Tax Income [Line Items]
Income tax year under examination	2017