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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Net sales	$ 578.9	$ 458.6	$ 1,613.2	$ 1,332.9
Component Products
Disaggregation Of Revenue [Line Items]
Net sales	34.5	28.4	106.7	84.5
Component Products | Security Products
Disaggregation Of Revenue [Line Items]
Net sales	25.8	21.2	79.3	65.2
Component Products | Marine Components
Disaggregation Of Revenue [Line Items]
Net sales	8.7	7.2	27.4	19.3
Real Estate Management And Development
Disaggregation Of Revenue [Line Items]
Net sales	44.6	13.3	63.1	24.5
Real Estate Management And Development | Land Sales
Disaggregation Of Revenue [Line Items]
Net sales	41.9	10.6	57.0	16.8
Real Estate Management And Development | Water Delivery
Disaggregation Of Revenue [Line Items]
Net sales	2.3	2.2	4.8	6.2
Real Estate Management And Development | Utility and Other
Disaggregation Of Revenue [Line Items]
Net sales	$ 0.4	$ 0.5	$ 1.3	$ 1.5