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		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation Of Revenue [Line Items]
Net sales	$ 559.7	$ 507.1	$ 1,090.3	$ 999.8
Component products
Disaggregation Of Revenue [Line Items]
Net sales	35.9	36.6	73.9	77.8
Component products | Security Products
Disaggregation Of Revenue [Line Items]
Net sales	28.2	25.6	58.1	53.0
Component products | Marine Components
Disaggregation Of Revenue [Line Items]
Net sales	7.7	11.0	15.8	24.8
Real estate management and development
Disaggregation Of Revenue [Line Items]
Net sales	$ 23.3	$ 27.3	$ 37.1	$ 52.5