Revenue - Disaggregation of Sales - Schedule of Disaggregates of Net Sales of our Component Products and Real Estate Management and Development Segments (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Net sales	$ 459.3	$ 479.6
Component Products
Disaggregation Of Revenue [Line Items]
Net sales	32.3	31.2
Component Products | Security Products
Disaggregation Of Revenue [Line Items]
Net sales	25.5	24.7
Component Products | Marine Components
Disaggregation Of Revenue [Line Items]
Net sales	6.8	6.5
Real Estate Management And Development
Disaggregation Of Revenue [Line Items]
Net sales	6.0	11.9
Real Estate Management And Development | Land Sales
Disaggregation Of Revenue [Line Items]
Net sales	3.6	9.5
Real Estate Management And Development | Water Delivery
Disaggregation Of Revenue [Line Items]
Net sales	1.9	1.9
Real Estate Management And Development | Utility and Other
Disaggregation Of Revenue [Line Items]
Net sales	$ 0.5	$ 0.5