Employee Benefit Plans - Schedule of Defined Benefit Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 12.9	$ 11.1
Defined benefit plan assets, percentage	100.00%	100.00%
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 0.2	$ 0.4
Defined benefit plan assets, percentage	1.30%	3.90%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 5.2	$ 8.1
Defined benefit plan assets, percentage	40.50%	72.30%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 0.7	$ 1.5
Defined benefit plan assets, percentage	5.60%	13.70%
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan assets, amount	$ 6.8	$ 1.1
Defined benefit plan assets, percentage	52.60%	10.10%