v3.25.2
Segment Results (Schedule Of Net Sales to External Customers) (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information [Line Items]        
Net sales to external customers $ 424.6 $ 365.1 $ 807.3 $ 691.4
Cost of goods sold 248.8 215.8 481.6 417.8
Gross profit (loss) 175.8 149.3 325.7 273.6
Selling, general and administrative expenses 84.5 80.6 162.5 146.0
Equity (earnings) from unconsolidated affiliates, net (31.9) (26.3) (58.5) (53.5)
Segment operating income (loss) 123.2 95.0 221.7 181.1
Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 424.6 365.1 807.3 691.4
Cost of goods sold 248.8 215.8 481.6 417.8
Gross profit (loss) 175.8 149.3 325.7 273.6
Selling, general and administrative expenses 84.5 80.6 162.5 146.0
Equity (earnings) from unconsolidated affiliates, net (31.9) (26.3) (58.5) (53.5)
Segment operating income (loss) 123.2 95.0 221.7 181.1
Depreciation and amortization 30.5 25.5 59.8 49.8
Purchases of property, plant and equipment 19.9 19.9 39.0 34.6
Mineral Fiber [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 267.0 250.2 512.1 489.8
Mineral Fiber [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 267.0 250.2 512.1 489.8
Cost of goods sold 156.7 147.5 304.7 293.2
Gross profit (loss) 110.3 102.7 207.4 196.6
Selling, general and administrative expenses 44.0 47.5 83.4 89.6
Equity (earnings) from unconsolidated affiliates, net (32.1) (26.5) (58.9) (53.9)
Segment operating income (loss) 98.4 81.7 182.9 160.9
Depreciation and amortization 22.1 19.7 42.9 39.6
Purchases of property, plant and equipment 16.8 16.0 31.4 27.6
Architectural Specialties [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 157.6 114.9 295.2 201.6
Architectural Specialties [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 157.6 114.9 295.2 201.6
Cost of goods sold 91.8 68.0 176.2 123.9
Gross profit (loss) 65.8 46.9 119.0 77.7
Selling, general and administrative expenses 40.2 32.7 78.6 55.8
Equity (earnings) from unconsolidated affiliates, net 0.0 0.0 0.0 0.0
Segment operating income (loss) 25.6 14.2 40.4 21.9
Depreciation and amortization 8.4 5.8 16.9 10.2
Purchases of property, plant and equipment 3.1 3.9 7.6 7.0
Unallocated Corporate [Member] | Unallocated Corporate [Member]        
Segment Reporting Information [Line Items]        
Cost of goods sold 0.3 0.3 0.7 0.7
Gross profit (loss) (0.3) (0.3) (0.7) (0.7)
Selling, general and administrative expenses 0.3 0.4 0.5 0.6
Equity (earnings) from unconsolidated affiliates, net 0.2 0.2 0.4 0.4
Segment operating income (loss) (0.8) (0.9) (1.6) (1.7)
Unallocated Corporate [Member] | Operating Segments [Member]        
Segment Reporting Information [Line Items]        
Net sales to external customers 0.0 0.0 0.0 0.0
Depreciation and amortization 0.0 0.0 0.0 0.0
Purchases of property, plant and equipment $ 0.0 $ 0.0 $ 0.0 $ 0.0