Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Employee deferrals deemed vested percentage upon contribution	100.00%
Defined contribution plan, cost	$ 1.4	$ 0.8
Maximum
Defined Benefit Plan Disclosure [Line Items]
Deferral percentage of base salary (up to)	80.00%
Deferral percentage of other compensation (up to)	100.00%