Commitments and Contingencies (Additional Information) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Legal fees	$ 0.4	$ 0.7
Environmental remediation (income) expense	(0.7)	$ 1.7	$ 0.7
Connecticut Voluntary Corrective Action Program
Loss Contingencies [Line Items]
Environmental remediation expense	1.7
Estimated total cleanup costs, accrual	$ 0.9