Pension and Post-Retirement Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Apr. 30, 2017	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Cash contribution to pension plan during the period			$ 10.0
Pension plan liabilities		$ 40.1		$ 40.2
Company contributions		$ 1.9	$ 1.8
Subsequent Event [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash contribution to pension plan during the period	$ 10.0