Employee Benefit Plans - Summary of Net Periodic Benefit Costs (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Service cost	$ 1.0	$ 0.8
Interest cost on projected benefit obligations	0.4	0.5
Expected return on plan assets	(0.1)	(0.1)
Amortization of actuarial net loss	0.5	0.1
Net periodic benefit costs	$ 1.8	$ 1.3