v3.25.2
Revenue (Schedule of Net Sales by Major Customer Channel within Each Segment) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Entity Wide Revenue Major Customer [Line Items]        
Net sales $ 424.6 $ 365.1 $ 807.3 $ 691.4
Mineral Fiber [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 267.0 250.2 512.1 489.8
Mineral Fiber [Member] | Distributors [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 200.2 184.9 380.2 354.2
Mineral Fiber [Member] | Home Centers [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 25.0 24.5 52.0 55.5
Mineral Fiber [Member] | Direct Customers [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 17.9 16.6 32.0 29.7
Mineral Fiber [Member] | Other [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 23.9 24.2 47.9 50.4
Architectural Specialties [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 157.6 114.9 295.2 201.6
Architectural Specialties [Member] | Distributors [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 70.0 55.5 124.3 109.3
Architectural Specialties [Member] | Direct Customers [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales 80.9 53.7 158.3 83.7
Architectural Specialties [Member] | Other [Member]        
Entity Wide Revenue Major Customer [Line Items]        
Net sales $ 6.7 $ 5.7 $ 12.6 $ 8.6