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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

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- Definition

Indicates title and position of individual or name of group identified as chief operating decision maker (CODM) for segment reporting.

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- Definition

Description of how chief operating decision maker (CODM) uses reported segment profit (loss) measure to assess performance and allocate resource.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Nature of Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Number Of Reportable Segments Not Disclosed Flag			true
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]			President and Chief Executive Officer [Member]
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description			Segment operating income (loss) is the measure of segment profit or loss reviewed by the CODM.
Mineral Fiber [Member]
Segment Reporting Information [Line Items]
Proceeds from Sale of Property, Plant, and Equipment			$ 1.0	$ 9.4
Gain on sale of properties	$ 0.3		$ 0.9	4.6
Asset impairment loss		$ 4.9
Architectural Specialties [Member]
Segment Reporting Information [Line Items]
Proceeds from Sale of Property, Plant, and Equipment				2.1
Gain on sale of properties	$ 0.0
WAVE [Member]
Segment Reporting Information [Line Items]
Equity interest percentage			50.00%
Land in Lancaster, Pennsylvania [Member] \| Mineral Fiber [Member]
Segment Reporting Information [Line Items]
Proceeds from Sale of Property, Plant, and Equipment				$ 12.8