Multi-employer Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plans [Line Items]
Entity Tax Identification Number	91-0351110
COMPANY CONTRIBUTIONS	$ 37.8	$ 32.8	$ 31.8
Metal and Electrical Engineering Industry Pension Fund
Multiemployer Plans [Line Items]
PENSION PLAN NUMBER	135668
COMPANY CONTRIBUTIONS	$ 33.9	27.8	27.9
Western Metal Industry Pension Plan
Multiemployer Plans [Line Items]
PENSION PLAN NUMBER	001
Entity Tax Identification Number	91-6033499
COMPANY CONTRIBUTIONS	$ 3.0	3.8	2.7
Other Plans
Multiemployer Plans [Line Items]
COMPANY CONTRIBUTIONS	$ 0.9	$ 1.2	$ 1.2