Retirement Plans and Other Post-Retirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Employer contribution of employee’s eligible earnings, percentage	10.00%
Pension Benefits [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension assets expected to revert		$ 33.0
Pension Benefits [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets remained in pension trust	$ 51.1