Armstrong World Industries (AWI) 10-Q 30 Jul 24 2024 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2024	Jul. 24, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q2
Entity Registrant Name	ARMSTRONG WORLD INDUSTRIES, INC.
Trading Symbol	AWI
Entity Central Index Key	0000007431
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		43,700,062
Entity Shell Company	false
Entity File Number	1-2116
Entity Tax Identification Number	23-0366390
Entity Address, Address Line One	2500 Columbia Avenue
Entity Address, City or Town	Lancaster
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	17603
City Area Code	717
Local Phone Number	397-0611
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	PA
Security Exchange Name	NYSE
Title of 12(b) Security	Common Stock, $0.01 par value per share

Condensed Consolidated Statemen

Condensed Consolidated Statements of Earnings and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Net sales	$ 365.1	$ 325.4	$ 691.4	$ 635.6
Cost of goods sold	215.8	201.4	417.8	399.5
Gross profit	149.3	124	273.6	236.1
Selling, general and administrative expenses	79.9	61.9	145.6	124.6
Loss related to change in fair value of contingent consideration	0.7	0	0.4	0
Equity (earnings) from unconsolidated affiliates, net	(26.3)	(24.9)	(53.5)	(45.7)
Operating income	95	87	181.1	157.2
Interest expense	11.1	9.2	20.1	17.9
Other non-operating (income), net	(3.2)	(2.2)	(6.3)	(4.6)
Earnings before income taxes	87.1	80	167.3	143.9
Income tax expense	21.2	19.8	41.5	36.4
Net earnings	65.9	60.2	125.8	107.5
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(0.4)	0.7	(1.2)	0.6
Derivative gain (loss), net	0.2	(0.2)	0.7	(2.4)
Pension and postretirement adjustments	(0.7)	(0.1)	(1.3)	0.1
Total other comprehensive (loss) income	(0.9)	0.4	(1.8)	(1.7)
Total comprehensive income	$ 65	$ 60.6	$ 124	$ 105.8
Net earnings per share of common stock:
Basic	$ 1.5	$ 1.34	$ 2.87	$ 2.38
Diluted	$ 1.5	$ 1.34	$ 2.86	$ 2.38
Average number of common shares outstanding:
Basic	43.8	44.9	43.8	45.2
Diluted	44	45	44	45.2

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 73.6	$ 70.8
Accounts and notes receivable, net	136	111
Inventories, net	113.8	104
Income taxes receivable	4	0.8
Other current assets	23.8	26.4
Total current assets	351.2	313
Property, plant, and equipment, less accumulated depreciation and amortization of $626.5 and $598.2, respectively	599.3	566.4
Operating lease assets	36.6	26.6
Finance lease assets	26.8	25.2
Prepaid pension costs	87.7	84.6
Investments in unconsolidated affiliates	29.6	17.4
Goodwill	193.8	175.5
Intangible assets, net	443.4	412.4
Other non-current assets	51.8	51.3
Total assets	1,820.2	1,672.4
Current liabilities:
Current installments of long-term debt	22.5	22.5
Accounts payable and accrued expenses	163	159.9
Operating lease liabilities	8	6.8
Finance lease liabilities	3	3
Income taxes payable	3.5	2.3
Total current liabilities	200	194.5
Long-term debt, less current installments	621.5	564.3
Operating lease liabilities	29.9	20.4
Finance lease liabilities	25.7	23.4
Postretirement benefit liabilities	40.8	42.4
Pension benefit liabilities	26.2	26.9
Other long-term liabilities	26.2	26.8
Income taxes payable	16	15
Deferred income taxes	164.9	166.9
Total non-current liabilities	951.2	886.1
Shareholders' equity:
Common stock, $0.01 par value per share, 200 million shares authorized, 63,166,429 shares issued and 43,787,757 shares outstanding as of June 30, 2024 and 63,054,340 shares issued and 43,902,061 shares outstanding as of December 31, 2023	0.6	0.6
Capital in excess of par value	595.1	591.7
Retained earnings	1,447.5	1,346.6
Treasury stock, at cost, 19,378,672 shares as of June 30, 2024 and 19,152,279 shares as of December 31, 2023	(1,267.7)	(1,242.4)
Accumulated other comprehensive (oss)	(106.5)	(104.7)
Total shareholders' equity	669	591.8
Total liabilities and shareholders' equity	$ 1,820.2	$ 1,672.4

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Property, plant and equipment, accumulated depreciation and amortization	$ 626.5	$ 598.2
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	63,166,429	63,054,340
Common stock, shares outstanding	43,787,757	43,902,061
Treasury stock, shares	19,378,672	19,152,279

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	AOCI Attributable to Parent
Beginning Balance at Dec. 31, 2022	$ 535	$ 0.6	$ 573.6	$ 1,169.9	$ (1,109)	$ (100.1)	[1]
Balance, shares at Dec. 31, 2022		45,572,185			17,364,635
Stock issuance, net, shares		61,745			(18)
Cash dividends - per common share	(23.3)			(23.3)
Share-based employee compensation	6.8		6.8
Net Income (Loss)	107.5			107.5
Other comprehensive income (loss)	(1.7)					(1.7)
Acquisition of treasury stock	(57.6)				$ (57.6)
Acquisition of treasury stock, shares		(810,645)			810,645
Ending Balance at Jun. 30, 2023	566.7	$ 0.6	580.4	1,254.1	$ (1,166.6)	(101.8)	[1]
Balance, shares at Jun. 30, 2023		44,823,285			18,175,262
Beginning Balance at Mar. 31, 2023	544.8	$ 0.6	577.2	1,205.5	$ (1,136.3)	(102.2)	[1]
Balance, shares at Mar. 31, 2023		45,217,244			17,731,828
Stock issuance, net, shares		49,417			58
Cash dividends - per common share	(11.6)			(11.6)
Share-based employee compensation	3.2		3.2
Net Income (Loss)	60.2			60.2
Other comprehensive income (loss)	0.4					0.4
Acquisition of treasury stock	(30.3)				$ (30.3)
Acquisition of treasury stock, shares		(443,376)			443,376
Ending Balance at Jun. 30, 2023	566.7	$ 0.6	580.4	1,254.1	$ (1,166.6)	(101.8)	[1]
Balance, shares at Jun. 30, 2023		44,823,285			18,175,262
Beginning Balance at Dec. 31, 2023	$ 591.8	$ 0.6	591.7	1,346.6	$ (1,242.4)	(104.7)	[1]
Balance, shares at Dec. 31, 2023	43,902,061	43,902,061			19,152,279
Stock issuance, net, shares		112,089
Cash dividends - per common share	$ (24.9)			(24.9)
Share-based employee compensation	3.4		3.4
Net Income (Loss)	125.8			125.8
Other comprehensive income (loss)	(1.8)					(1.8)
Acquisition of treasury stock	(25.3)				$ (25.3)
Acquisition of treasury stock, shares		(226,393)			226,393
Ending Balance at Jun. 30, 2024	$ 669	$ 0.6	595.1	1,447.5	$ (1,267.7)	(106.5)	[1]
Balance, shares at Jun. 30, 2024	43,787,757	43,787,757			19,378,672
Beginning Balance at Mar. 31, 2024	$ 626.8	$ 0.6	595.3	1,394.1	$ (1,257.6)	(105.6)	[1]
Balance, shares at Mar. 31, 2024		43,777,371			19,294,861
Stock issuance, net, shares		94,197
Cash dividends - per common share	(12.5)			(12.5)
Share-based employee compensation	(0.2)		(0.2)
Net Income (Loss)	65.9			65.9
Other comprehensive income (loss)	(0.9)					(0.9)
Acquisition of treasury stock	(10.1)				$ (10.1)
Acquisition of treasury stock, shares		(83,811)			83,811
Ending Balance at Jun. 30, 2024	$ 669	$ 0.6	$ 595.1	$ 1,447.5	$ (1,267.7)	$ (106.5)	[1]
Balance, shares at Jun. 30, 2024	43,787,757	43,787,757			19,378,672
[1] (1) Amounts are net of tax.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Stockholders' Equity [Abstract]
Dividends declared	$ 0.28	$ 0.254	$ 0.56	$ 0.508

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Cash flows from operating activities:
Net Income (Loss)	$ 125.8	$ 107.5
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	49.8	43.1
Deferred income taxes	(1.8)	(1)
Share-based compensation	8.7	7.9
Equity earnings from unconsolidated affiliates	(53.5)	(45.7)
Loss related to change in fair value of contingent consideration	0.4	0
Payment of contingent consideration in excess of acquisition-date fair value	0	(5)
Other non-cash adjustments, net	0	(0.1)
Changes in operating assets and liabilities:
Receivables	(29.5)	(10.5)
Inventories	(2)	0.9
Accounts payable and accrued expenses	(5.7)	(1.3)
Income taxes receivable and payable, net	(1)	4.6
Other assets and liabilities	(7.5)	(6.5)
Net cash provided by operating activities	83.7	93.9
Cash flows from investing activities:
Purchases of property, plant and equipment	(34.6)	(41.5)
Return of investment from joint venture	46.2	44.6
Cash paid for acquisitions, net of cash acquired	(93.9)	(10)
Investment in unconsolidated affiliate	(5.5)	0
Proceeds from the sale of assets	2.1	0
Proceeds from company owned life insurance, net	4.3	0.9
Net cash used for investing activities	(81.4)	(6)
Cash flows from financing activities:
Proceeds from revolving credit facility	138	30
Payments of revolving credit facility	(70)	(30)
Payments of long-term debt	(11.3)	0
Payments for finance leases	(1.5)	(1.2)
Dividends paid	(24.9)	(23.1)
Payments from share-based compensation plans, net of tax	(4.2)	(1.1)
Payment of acquisition-related contingent consideration	0	(10.2)
Payments for treasury stock acquired	(25)	(57)
Net cash provided by (used for) financing activities	1.1	(92.6)
Effect of exchange rate changes on cash and cash equivalents	(0.6)	0.3
Net increase (decrease) in cash and cash equivalents	2.8	(4.4)
Cash and cash equivalents at beginning of year	70.8	106
Cash and cash equivalents at end of period	73.6	101.6
Supplemental Cash Flow Disclosures:
Interest paid	19	17.3
Income tax payments, net	44.3	32.8
Amounts in accounts payable for capital expenditures	$ 2.1	$ 1.7

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Pay vs Performance Disclosure
Net Income (Loss)	$ 65.9	$ 60.2	$ 125.8	$ 107.5

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Jun. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Business and Basis of Presentat

Business and Basis of Presentation	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Business and Basis of Presentation	NOTE 1. BUSINESS AND BASIS OF PRESENTATION Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to “AWI,” the “Company,” “we,” “our” or “us” in these notes, we are referring to AWI and its subsidiaries. Except as disclosed in this note, the accounting policies used in preparing the Condensed Consolidated Financial Statements in this Form 10-Q are the same as those used in preparing the Consolidated Financial Statements for the year ended December 31, 2023. These statements should therefore be read in conjunction with the Consolidated Financial Statements and notes that are included in the Annual Report on Form 10-K for the fiscal year ended December 31, 2023. In the opinion of management, all adjustments of a normal recurring nature have been included to provide a fair statement of the results for the reporting periods presented. Operating results for the second quarter and first six months of 2024 and 2023 included in this report are unaudited. Quarterly results are not necessarily indicative of annual earnings, primarily due to the different level of sales in each quarter of the year and the possibility of changes in general economic conditions. These Condensed Consolidated Financial Statements are prepared in accordance with U.S. generally accepted accounting principles. The statements include management estimates and judgments, where appropriate. Management utilizes estimates to record many items, including certain asset values, contingent purchase price liabilities, allowances for bad debts, inventory obsolescence and lower of cost and net realizable value charges, warranty reserves, workers’ compensation, general liability and environmental claims, and income taxes. When preparing an estimate, management determines the amount based upon the consideration of relevant information and may confer with outside parties, including external counsel. Actual results may differ from these estimates. Acquisitions and Investments in Unconsolidated Affiliates In April 2024, we acquired all of the issued and outstanding membership interests in 3form, LLC (“3form”), a subsidiary of Hunter Douglas, Inc. based in Salt Lake City, Utah. 3form is a designer and manufacturer of architectural resin and glass products used for specialty walls, partitions and ceilings. The operations, assets and liabilities of 3form are included in our Architectural Specialties segment. In January 2024, we entered into a strategic partnership and equity investment in Overcast Innovations LLC (“Overcast”) with McKinstry Essention, LLC whereby we contributed $ 5.5 million in exchange for a 19.5 % ownership interest in Overcast, with future rights to increase our ownership interest. Overcast is a solutions company offering prefabricated ceiling cloud systems, modular grid platforms and engineering design services to reduce waste and inefficiencies in the built environment. Our investment and equity earnings in Overcast are included in our Unallocated Corporate segment. In October 2023, we acquired a portion of the business and certain assets of Insolcorp, LLC (“Insolcorp”), based in Albemarle, North Carolina, used to develop, test and manufacture energy saving products deployed in building and roofing installations. The acquired operations, assets and liabilities of Insolcorp are included in our Mineral Fiber segment. In July 2023, we acquired all of the issued and outstanding stock of BOK Modern, LLC (“BOK”), based in San Rafael, California. BOK is a designer of metal facade architectural solutions. The operations, assets and liabilities of BOK are included in our Architectural Specialties segment. Recently Issued Accounting Standards In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Improvements to Reportable Segment Disclosures,” which modifies reportable segment disclosure requirements. This ASU expands annual and interim reportable segment disclosures, including: disclosure of the title and position of our chief operating decision maker (“CODM”), interim and annual disclosure of significant reportable segment expenses that are components of segment profit or loss information provided to the CODM, and interim disclosure of all annual reportable segment profit or loss and asset data currently only required to be disclosed annually. This guidance is effective for annual periods beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. The adoption of this standard is not expected to have an impact on our financial statements, but will result in significantly expanded reportable segment disclosures. In December 2023, the FASB issued ASU 2023-09, “Improvements to Income Tax Disclosures,” which modifies the disclosure requirements for income taxes. This ASU requires disclosure of tabular statutory to effective rate reconciliation in both percentages and dollars, additional disaggregated rate reconciliation categories and disaggregation of both income taxes paid and income tax expense by jurisdiction. This guidance is effective for annual periods beginning after December 15, 2024. We expect this ASU to only impact our disclosures with no impact to our result of operations, cash flows and financial condition.

Segment Results

Segment Results	6 Months Ended
	Jun. 30, 2024
Segment Reporting [Abstract]
Segment Results	NOTE 2. SEGMENT RESULTS Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales Mineral Fiber $ 250.2 $ 234.0 $ 489.8 $ 462.4 Architectural Specialties 114.9 91.4 201.6 173.2 Total net sales $ 365.1 $ 325.4 $ 691.4 $ 635.6 Our product-based Mineral Fiber and Architectural Specialties segment net sales represent the product-based group offerings we sell to external customers. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Segment operating income (loss) Mineral Fiber $ 81.7 $ 75.5 $ 160.9 $ 139.3 Architectural Specialties 14.2 12.2 21.9 19.4 Unallocated Corporate ( 0.9 ) ( 0.7 ) ( 1.7 ) ( 1.5 ) Total consolidated operating income $ 95.0 $ 87.0 $ 181.1 $ 157.2 Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Total consolidated operating income $ 95.0 $ 87.0 $ 181.1 $ 157.2 Interest expense 11.1 9.2 20.1 17.9 Other non-operating (income), net ( 3.2 ) ( 2.2 ) ( 6.3 ) ( 4.6 ) Earnings before income taxes $ 87.1 $ 80.0 $ 167.3 $ 143.9 June 30, 2024 December 31, 2023 Segment assets Mineral Fiber $ 1,098.1 $ 1,091.9 Architectural Specialties 549.6 421.1 Unallocated Corporate 172.5 159.4 Total consolidated assets $ 1,820.2 $ 1,672.4

Revenue

Revenue	6 Months Ended
	Jun. 30, 2024
Revenue from Contract with Customer [Abstract]
Revenue	NOTE 3. REVENUE Disaggregation of Revenues Our Mineral Fiber and Architectural Specialties operating segments both manufacture and sell ceiling and wall systems (primarily mineral fiber, fiberglass wool, metal, wood, felt, wood fiber, architectural resin and glass, and glass-reinforced-gypsum) throughout the Americas. We disaggregate revenue based on our product-based segments and major customer channels, as they represent the most appropriate depiction of how the nature, amount and timing of revenues and cash flows are affected by economic factors. Net sales by major customer channel are as follows: Distributors – represents net sales to building materials distributors who re-sell our products to contractors, subcontractors’ alliances, large architect and design firms, and major facility owners. Geographically, this category includes sales throughout the U.S., Canada, and Latin America. Home centers – represents net sales to home centers, such as Lowe’s Companies, Inc. and The Home Depot, Inc. This category includes sales primarily to U.S. customers. Direct customers – represents net sales to contractors, subcontractors, and large architect and design firms. This category includes sales primarily to U.S. customers. Other – represents net sales to independent retailers and certain national account customers, including wholesalers who re-sell our products to dealers who service builders, contractors, online customers, major facility owners, group purchasing organizations, maintenance, repair and operating entities and original product manufacturers. Geographically, this category includes sales throughout the U.S., Canada, and Latin America. The following tables provide net sales by major customer channel within our Mineral Fiber and Architectural Specialties segments for the three and six months ended June 30, 2024 and 2023: Three Months Ended Six Months Ended June 30, June 30, Mineral Fiber 2024 2023 2024 2023 Distributors $ 184.9 $ 174.6 $ 354.2 $ 334.4 Home centers 24.5 23.4 55.5 54.5 Direct customers 16.6 15.2 29.7 29.9 Other 24.2 20.8 50.4 43.6 Total $ 250.2 $ 234.0 $ 489.8 $ 462.4 Three Months Ended Six Months Ended June 30, June 30, Architectural Specialties 2024 2023 2024 2023 Distributors $ 55.5 $ 45.9 $ 109.3 $ 85.1 Direct customers 53.7 44.4 83.7 86.4 Other 5.7 1.1 8.6 1.7 Total $ 114.9 $ 91.4 $ 201.6 $ 173.2

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2024
Business Combinations [Abstract]
Acquisitions	NOTE 4. ACQUISITIONS We account for acquisitions under the acquisition method and the results of operations of acquired operations are included in the Condensed Consolidated Financial Statements from the acquisition date. Acquisition related costs are expensed as incurred. We allocate total consideration to the assets acquired and liabilities assumed based on their estimated fair values, with the remaining unallocated amount recorded as goodwill. Definite-lived intangible assets are amortized over the estimated useful life on a straight-line basis and recorded as a component of operating income. The fair value of acquired intangible assets is estimated by applying discounted cash flow models based on significant level 3 inputs not observable in the market. Key assumptions are developed based on each acquirees’ historical experience, future projections and comparable market data including future cash flows, long-term growth rates, implied royalty rates, attrition rates and discount rates. Acquisition-related contingent consideration that is classified as a liability is measured at fair value as of the acquisition date. The fair value of contingent consideration is remeasured at each reporting period, and any future changes in the fair value of contingent consideration recorded in reporting periods after the acquisition date are recorded within loss related to change in fair value of contingent consideration on our Condensed Consolidated Statements of Earnings and Comprehensive Income. 3form In April 2024, we acquired the issued and outstanding membership interests in 3form for a purchase price of $ 93.9 million, net of $ 0.5 million of cash acquired, subject to customary post-closing adjustments for working capital. The total fair value of tangible assets acquired, less liabilities assumed, was $ 36.3 million. The fair value of significant classes of assets acquired and liabilities assumed included accounts receivable of $ 6.9 million, inventory of $ 7.9 million, property, plant and equipment of $ 37.5 million, operating lease assets and liabilities of $ 10.0 million and accounts payable and accrued liabilities of $ 17.5 million. The total fair value of identifiable intangible assets acquired was $ 39.6 million, resulting in $ 18.5 million of goodwill. The following table summarizes the fair values of identifiable intangible assets acquired, and their estimated useful lives: Fair Value at Acquisition Date Estimated Useful Life Customer relationships $ 16.6 5 years Trademarks and brand names 15.0 15 years Non-compete agreements 3.8 5 years Software 1.9 5 years Backlog 1.2 1 year Developed technology 1.1 16 years Total identifiable intangible assets $ 39.6 Goodwill from the 3form acquisition relates to many factors, including the technical competencies and capabilities of the acquired workforce and our strategic intent to integrate and leverage those competencies and capabilities to advance and expand our portfolio of solutions and offerings. All of the acquired goodwill is deductible for tax purposes. Valuations for assets acquired and liabilities assumed are based on preliminary estimates that are subject to revisions and may result in adjustments to preliminary values as valuations are finalized. The following table summarizes aggregate unaudited as reported and pro forma information assuming the acquisition of 3form had occurred on January 1, 2023. The unaudited pro forma results include the depreciation and amortization associated with the acquired assets. The unaudited pro forma results do not include any expected benefits from the 3form acquisition. Accordingly, the unaudited pro forma results are not necessarily indicative of either future results of operations or results that might have been achieved had the acquisition been consummated as of January 1, 2023. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales, pro forma $ 388.3 $ 348.0 $ 737.7 $ 683.9 Net sales, as reported 365.1 325.4 691.4 635.6 Earnings before income taxes, pro forma 89.8 79.4 170.2 143.4 Earnings before income taxes, as reported 87.1 80.0 167.3 143.9 For the three and six months ended June 30, 2024, net sales of $ 20.4 and $ 23.4 , respectively, from BOK and 3form were included in our Condensed Consolidated Statements of Operations and Comprehensive Income since the acquisition dates. Software-Related Intellectual Property In May 2023, we acquired a co-ownership interest in certain software-related intellectual property for a total purchase price of $ 11.0 million, of which $ 10.0 million was paid in the second quarter of 2023 and an additional $ 1.0 million was paid in the fourth quarter of 2023. As a result of this transaction, the total fair value of identifiable intangible assets acquired was $ 6.5 million of software and $ 4.5 million of developed technology, which are being amortized over a weighted-average life of 5 and 17 years, respectively.

Accounts and Notes Receivable

Accounts and Notes Receivable	6 Months Ended
	Jun. 30, 2024
Receivables [Abstract]
Accounts and Notes Receivable	NOTE 5. ACCOUNTS AND NOTES RECEIVABLE June 30, 2024 December 31, 2023 Customer receivables $ 130.3 $ 102.1 Miscellaneous receivables 9.5 11.8 Less allowance for warranties, discounts and losses ( 3.8 ) ( 2.9 ) Accounts and notes receivable, net $ 136.0 $ 111.0 We sell our products to select, pre-approved customers whose businesses are affected by changes in economic and market conditions. We consider these factors and the financial condition of each customer when establishing our allowance for losses from doubtful accounts.

Inventories

Inventories	6 Months Ended
	Jun. 30, 2024
Inventory Disclosure [Abstract]
Inventories	NOTE 6. INVENTORIES June 30, 2024 December 31, 2023 Finished goods $ 60.7 $ 55.1 Goods in process 7.2 5.1 Raw materials and supplies 71.6 66.7 Less LIFO reserves ( 25.7 ) ( 22.9 ) Total inventories, net $ 113.8 $ 104.0

Other Current Assets

Other Current Assets	6 Months Ended
	Jun. 30, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Current Assets	NOTE 7. OTHER CURRENT ASSETS June 30, 2024 December 31, 2023 Prepaid expenses $ 15.2 $ 15.9 Assets held for sale 4.6 6.7 Fair value of derivative assets 1.5 1.1 Other 2.5 2.7 Total other current assets $ 23.8 $ 26.4 As of June 30, 2024 , assets held for sale included the land and property, plant and equipment of our idled Mineral Fiber plant in St. Helens, Oregon. As of December 31, 2023, assets held for sale included the land and property, plant and equipment of our idled Mineral Fiber plant in St. Helens, Oregon and a building and related land of an Architectural Specialties design center in Chicago, Illinois. During the second quarter of 2024, we sold the Architectural Specialties design center in Chicago, Illinois for total proceeds of $ 2.1 million, with no gain or loss recorded upon sale.

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	6 Months Ended
	Jun. 30, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	NOTE 8. INVESTMENTS IN UNCONSOLIDATED AFFILIATES Investments in unconsolidated affiliates include our 50 % equity interest in Worthington Armstrong Venture (“ WAVE”), our joint venture with Worthington Enterprises, Inc., and our 19.5 % equity interest in Overcast. Both the WAVE joint venture and Overcast investment are reflected within our Condensed Consolidated Financial Statements using the equity method of accounting. WAVE is reflected as a component of our Mineral Fiber segment while Overcast is included as a component of our Unallocated Corporate segment. Condensed financial statement data for WAVE is summarized below. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales $ 126.1 $ 116.1 $ 251.9 $ 225.6 Gross profit 71.1 70.1 147.8 132.4 Net earnings 55.2 51.6 112.2 95.4 The following table presents equity (earnings) losses from our unconsolidated affiliates for the three and six months ended June 30, 2024 and 2023: Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 WAVE $ ( 26.5 ) $ ( 24.9 ) $ ( 53.9 ) $ ( 45.7 ) Overcast 0.2 - 0.4 - Equity (earnings) from unconsolidated affiliates, net $ ( 26.3 ) $ ( 24.9 ) $ ( 53.5 ) $ ( 45.7 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Jun. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	NOTE 9. GOODWILL AND INTANGIBLE ASSETS The following table details amounts related to our goodwill and intangible assets as of June 30, 2024 and December 31, 2023: June 30, 2024 December 31, 2023 Estimated Gross Accumulated Amortization Gross Accumulated Amortization Amortizing intangible assets Customer relationships 2 - 20 years $ 200.1 $ 157.9 $ 183.6 $ 152.1 Developed technology 13 - 20 years 103.1 85.0 101.4 84.4 Software 5 - 7 years 17.5 6.0 15.6 4.6 Trademarks and brand names 3 - 20 years 21.2 3.8 6.2 3.4 Non-compete agreements 3 - 5 years 9.7 4.4 6.1 3.8 Other Various 4.0 0.4 2.8 0.2 Total $ 355.6 $ 257.5 $ 315.7 $ 248.5 Non-amortizing intangible assets Trademarks and brand names Indefinite 345.3 345.2 Total intangible assets $ 700.9 $ 660.9 Goodwill Indefinite $ 193.8 $ 175.5 The net increase in goodwill as of June 30, 2024 compared to December 31, 2023 was due to the acquisition of 3form, net of foreign exchange movements. Six Months Ended June 30, 2024 2023 Amortization expense $ 9.4 $ 7.1

Other Non-Current Assets

Other Non-Current Assets	6 Months Ended
	Jun. 30, 2024
Other Assets, Noncurrent Disclosure [Abstract]
Other Non-Current Assets	NOTE 10. OTHER NON-CURRENT ASSETS June 30, 2024 December 31, 2023 Cash surrender value of company-owned life insurance policies $ 37.9 $ 40.3 Investment in employee deferred compensation plans 12.4 8.3 Fair value of derivative assets 0.3 1.8 Other 1.2 0.9 Total other non-current assets $ 51.8 $ 51.3

Accounts Payable And Accrued Ex

Accounts Payable And Accrued Expenses	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Accounts Payable And Accrued Expenses	NOTE 11. ACCOUNTS PAYABLE AND ACCRUED EXPENSES June 30, 2024 December 31, 2023 Payables, trade and other $ 106.4 $ 91.0 Employment costs 21.2 33.6 Current portion of pension and postretirement liabilities 8.0 8.0 Other 27.4 27.3 Total accounts payable and accrued expenses $ 163.0 $ 159.9

Income Tax Expense

Income Tax Expense	6 Months Ended
	Jun. 30, 2024
Income Tax Disclosure [Abstract]
Income Tax Expense	NOTE 12. INCOME TAX EXPENSE Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Earnings before income taxes $ 87.1 $ 80.0 $ 167.3 $ 143.9 Income tax expense 21.2 19.8 41.5 36.4 Effective tax rate 24.3 % 24.8 % 24.8 % 25.3 % The effective tax rate for the second quarter and first six months of 2024 was lower compared to the same periods in 2023 due primarily to increased excess tax benefits from stock-based compensation deductions. It is reasonably possible that the amount of unrecognized tax benefits could significantly increase or decrease within the next twelve months. However, an estimate of the range of reasonably possible outcomes cannot be reliably made at this time. Changes to unrecognized tax benefits could result from the expiration of statutes of limitations, the completion of ongoing examinations, or other unforeseen circumstances.

Debt

Debt	6 Months Ended
	Jun. 30, 2024
Debt Disclosure [Abstract]
Debt	NOTE 13. DEBT Our long-term debt is comprised of borrowings outstanding under our $ 950.0 million variable rate senior credit facility, which is comprised of a $ 500.0 million revolving credit facility (with a $ 150.0 million sublimit for letters of credit) and a $ 450.0 million Term Loan A. As of June 30, 2024 and December 31, 2023, the principal balance of our Term Loan A was $ 438.7 million and $ 450.0 million, respectively. As of June 30, 2024 and December 31, 2023, borrowings outstanding under our revolving credit facility were $ 208.0 million and $ 140.0 million, respectively. We also have a $ 25.0 million bi-lateral letter of credit facility. We utilize lines of credit and other commercial commitments to ensure that adequate funds are available to meet operating requirements. Letters of credit are currently arranged through our revolving credit facility and our bi-lateral facility. Letters of credit may be issued to third party suppliers, insurance companies and financial institutions and typically can only be drawn upon in the event of AWI’s failure to pay its obligations to the beneficiary. The following table presents details related to our letters of credit facilities: June 30, 2024 Financing Arrangements Limit Used Available Bi-lateral facility $ 25.0 $ 7.4 $ 17.6 Revolving credit facility 150.0 - 150.0 Total $ 175.0 $ 7.4 $ 167.6

Pensions and Other Benefit Prog

Pensions and Other Benefit Programs	6 Months Ended
	Jun. 30, 2024
Retirement Benefits [Abstract]
Pensions and Other Benefit Programs	NOTE 14. PENSIONS AND OTHER BENEFIT PROGRAMS Following are the components of net periodic benefit costs (credits): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 U.S. defined benefit plans: Pension benefits Service cost of benefits earned during the period $ 0.6 $ 0.6 $ 1.2 $ 1.3 Interest cost on projected benefit obligation 4.2 4.3 8.4 8.5 Expected return on plan assets ( 6.1 ) ( 6.3 ) ( 12.2 ) ( 12.5 ) Amortization of net actuarial loss 1.3 1.4 2.6 2.7 Net periodic pension cost $ - $ - $ - $ - Retiree health and life insurance benefits Interest cost on projected benefit obligation $ 0.5 $ 0.7 $ 1.0 $ 1.4 Amortization of prior service credit - ( 0.1 ) ( 0.1 ) ( 0.1 ) Amortization of net actuarial gain ( 2.1 ) ( 1.4 ) ( 4.2 ) ( 2.9 ) Net periodic postretirement credit $ ( 1.6 ) $ ( 0.8 ) $ ( 3.3 ) $ ( 1.6 ) Excluded from the table above is the net periodic pension cost associated with an unfunded defined benefit pension plan in Germany that was not included as part of prior dispositions. This plan is reported as a component of our Unallocated Corporate segment. Net periodic pension cost for this plan was immaterial for the three and six months ended June 30, 2024 and 2023. The service cost component of net benefit cost has been presented in the Condensed Consolidated Statements of Earnings and Comprehensive Income within cost of goods sold and selling, general and administrative (“ SG&A”) expenses for all periods presented, which are the same line items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are presented in the Condensed Consolidated Statements of Earnings and Comprehensive Income separately from the service cost component within other non-operating income, net.

Financial Instruments and Conti

Financial Instruments and Contingent Consideration	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Financial Instruments and Contingent Consideration	NOTE 15. FINANCIAL INSTRUMENTS AND CONTINGENT CONSIDERATION We do not hold or issue financial instruments for trading purposes. The estimated fair values of our financial instruments and contingent consideration are as follows: June 30, 2024 December 31, 2023 Carrying Estimated Carrying Estimated Assets (liabilities), net: Total long-term debt, including current portion $ ( 644.0 ) $ ( 644.0 ) $ ( 586.8 ) $ ( 586.8 ) Interest rate swap contracts 1.3 1.3 ( 0.4 ) ( 0.4 ) Acquisition-related contingent consideration ( 2.0 ) ( 2.0 ) ( 1.6 ) ( 1.6 ) The carrying amounts of cash and cash equivalents, customer receivables and accounts payable approximate fair value because of the short-term maturity of these instruments. The fair value estimates of long-term debt are based on data for our Term Loan A debt provided by a major financial institution. The fair value estimates for interest rate swap contracts are estimated with the assistance of third-party valuation experts and verified by obtaining quotes from major financial institutions. We engaged an independent, third-party valuation specialist to determine the fair value estimate for acquisition-related contingent consideration payable based on performance, which was measured using a Monte Carlo simulation. As of June 30, 2024 a nd December 31, 2023, acquisition-related contingent consideration liabilities represented additional cash consideration payable related to our acquisitions of Insolcorp and BOK that will be paid upon the final achievement of certain financial and performance milestones. As of June 30, 2024, $ 0.5 million of acquisition-related contingent consideration was classified as accounts payable and other accrued expenses, while $ 1.5 million was classified as other long-term liabilities on our Condensed Consolidated Balance Sheet. As of December 31, 2023, $ 1.6 million was classified as other long-term liabilities on our Condensed Consolidated Balance Sheet. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. Three levels of inputs may be used to measure fair value: Level 1 — Quoted prices in active markets for identical assets or liabilities; Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data; or Level 3 — Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The fair value measurement of assets and liabilities measured at fair value on a recurring basis and reported on the Condensed Consolidated Balance Sheets is summarized below: June 30, 2024 December 31, 2023 Fair value based on Fair value based on Other Other Other Other Level 2 Level 3 Level 2 Level 3 Assets (liabilities), net: Interest rate swap contracts $ 1.3 $ - $ ( 0.4 ) $ - Acquisition-related contingent consideration - ( 2.0 ) - ( 1.6 ) Acquisition-related contingent considerati on of $ 2.0 million and $ 1.6 million as of June 30, 2024 and December 31, 2023, respectively, was measured with the use of significant unobservable inputs, which included financial proj ections over respective earn-out periods, the volatility of the underlying financial metrics and estimated discount rates. All changes in acquisition-related contingent consideration liabilities subsequent to the initial acquisition-date measurements were recorded as a component of operating income on our Condensed Consolidated Statements of Earnings and Comprehensive Income. The following table summarizes the weighted-average of the significant unobservable inputs as o f June 30, 2024: BOK Insolcorp Unobservable input Volatility 23.2 % 21.2 % Discount rates 5.1 % 5.1 % The changes in fair value of the acquisition-related contingent consideration liabilities for the three months ended June 30, 2024 and the six months ended June 30, 2024 and 2023 were as follows: Three Months Ended Six Months Ended June 30, June 30, 2024 2024 2023 Fair value of contingent consideration as of beginning of period $ 1.3 $ 1.6 $ 15.2 Cash consideration paid - - ( 15.2 ) Loss related to change in fair value of contingent consideration 0.7 0.4 - Fair value of contingent consideration as of end of period $ 2.0 $ 2.0 $ - During the three and six months ended June 30, 2024, the changes in fair value were primarily due to changes in financial projections over each entity’s earn-out periods and due to changes in valuation inputs. During the six months ended June 30, 2023, we paid $ 15.2 million of additional cash consideration, which represented the final achievement of certain financial and performance milestones through December 31, 2022 for the July 2020 acquisition of TURF Design, Inc. The additional cash consideration paid was classified as cash flows from financing activities in our Condensed Consolidated Statements of Cash Flows, up to the acquisition date fair value. The portion of additional cash consideration paid in excess of the acquisition date fair value was classified as cash flows from operating activities in our Condensed Consolidated Statements of Cash Flows.

Derivative Financial Instrument

Derivative Financial Instruments	6 Months Ended
	Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	NOTE 16. DERIVATIVE FINANCIAL INSTRUMENTS We are exposed to market risk from changes in foreign exchange rates, interest rates and commodity prices that could impact our results of operations, cash flows and financial condition. We use interest rate derivatives to manage our exposures to interest rates. At inception, interest rate swap derivatives that we designate as hedging instruments are formally documented as a hedge of a forecasted transaction or cash flow hedge. We also formally assess, both at inception and at least quarterly thereafter, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in the cash flows of the hedged item. If it is determined that a derivative ceases to be a highly effective hedge, or if the anticipated transaction is no longer probable of occurring, we discontinue hedge accounting, and any future mark-to-market adjustments are recognized in earnings. We use derivative financial instruments as risk management tools and not for speculative trading purposes. Counterparty Risk We only enter into derivative transactions with established financial institution counterparties having an investment-grade credit rating. We monitor counterparty credit ratings on a regular basis. All of our derivative transactions with counterparties are governed by master International Swap and Derivatives Association agreements (“ISDAs”) with netting arrangements. These agreements can limit our exposure in situations where we have gain and loss positions outstanding with a single counterparty. We do not post nor do we receive cash collateral with any counterparty for our derivative transactions. These ISDAs do not have any credit contingent features; however, a default under our bank credit facility would trigger a default under these agreements. Exposure to individual counterparties is controlled and we consider the risk of counterparty default to be negligible. Interest Rate Risk We utilize interest rate swaps to minimize the fluctuations in earnings caused by interest rate volatility. These swaps are designated as cash flow hedges against changes in interest rates for a portion of our variable rate debt. The following table summarizes our interest rate swaps as of June 30, 2024: Coverage Period Notional Risk Coverage Trade Date March 2021 to March 2025 $ 100.0 USD-SOFR November 28, 2018 November 2023 to December 2025 $ 50.0 USD-SOFR October 23, 2023 March 2024 to June 2026 $ 50.0 USD-SOFR March 25, 2024 November 2023 to December 2026 $ 50.0 USD-SOFR October 10, 2023 March 2024 to June 2027 $ 50.0 USD-SOFR March 27, 2024 November 2023 to November 2027 $ 50.0 USD-SOFR September 29, 2023 June 2024 to June 2028 $ 50.0 USD-SOFR June 26, 2024 Under the terms of the interest rate swap with a November 28, 2018 trade date above, we pay a fixed rate monthly and receive a floating rate based on the Secured Overnight Financing Rate (“SOFR”), inclusive of a 0 % floor. Under the terms of all remaining interest rate swaps above, we pay a fixed rate monthly and receive a floating rate based on SOFR. Financial Statement Impacts The following tables detail amounts related to our derivatives as of June 30, 2024 and December 31, 2023. We did not have any derivative assets or liabilities not designated as hedging instruments as of June 30, 2024 or December 31, 2023. The derivative asset amounts below are shown gross and have not been netted. Derivative Assets Derivative Liabilities Fair Value Fair Value Balance Sheet June 30, December 31, Balance Sheet June 30, December 31, Interest rate swap contracts Other current assets $ 1.5 $ 1.1 Accounts payable and accrued expenses $ - $ 0.1 Interest rate swap contracts Other non-current assets 0.3 1.8 Other long-term liabilities 0.5 3.2 Amount of Gain Location of Gain Reclassified from Gain Reclassified Six Months Ended Three Months Ended Six Months Ended June 30, June 30, June 30, 2024 2023 2024 2023 2024 2023 Derivatives in cash flow hedging relationships Interest rate swap contracts $ 4.3 $ 2.1 Interest expense $ 1.2 $ 2.9 $ 3.3 $ 5.3 As of June 30, 2024, the amount of existing gains in Accumulated Other Comprehensive Income (“AOCI”) expected to be recognized in net earnings over the next twelve months wa s $ 3.4 million.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2024
Stockholders' Equity Note [Abstract]
Shareholders' Equity	NOTE 17. SHAREHOLDERS’ EQUITY Common Stock Repurchase Plan On July 29, 2016, our Board of Directors approved our share repurchase program authorizing us to repurchase up to $ 150.0 million of our outstanding shares of common stock (the “Program”). Since inception of the Program, we have been further authorized to repurchase up to an aggregate of $ 1,700.0 million of our outstanding shares of common stock through December 31, 2026 . We had $ 691.8 million remaining under the Board’s repurchase authorization as of June 30, 2024. Repurchases under the Program may be made through open market, block and privately negotiated transactions, including Rule 10b5-1 plans, at such times and in such amounts as management deems appropriate, subject to market and business conditions, regulatory requirements and other factors. The Program does not obligate AWI to repurchase any particular amount of common stock and may be suspended or discontinued at any time without notice. During the three months ended June 30, 2024, we repu rchased 0.1 million shares under the Program for a total cost of $ 10.0 million, excluding commissions and taxes, or an average price of $ 119.32 per sh are. During the six months ended June 30, 2024, we repurchased 0.2 million shares under the Program for a total cost of $ 25.0 million, excluding commissions and taxes, or an average price of $ 110.43 per share. Since inception, we have repurchased 14.4 million shares under the Program for a total cost of $ 1,008.2 million, excluding commissions and taxes, or an average price of $ 69.97 per share. Dividends In February and April 2024, our Board of Directors declared a $ 0.28 per share quarterly dividend, which was paid to shareholders in March and May 2024 . On July 24, 2024, our Board of Directors declared a $ 0.28 per share quarterly dividend to be paid on August 22, 2024 . Accumulated Other Comprehensive (Loss) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, March 31, 2024 $ 0.2 $ 1.0 $ ( 106.8 ) $ ( 105.6 ) Other comprehensive (loss) income before reclassifications, - , ($ 0.3 ), - and ($ 0.3 ) ( 0.4 ) 1.1 - 0.7 Amounts reclassified from accumulated other - ( 0.9 ) ( 0.7 ) ( 1.6 ) Net current period other comprehensive (loss) income ( 0.4 ) 0.2 ( 0.7 ) ( 0.9 ) Balance, June 30, 2024 $ ( 0.2 ) $ 1.2 $ ( 107.5 ) $ ( 106.5 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, December 31, 2023 $ 1.0 $ 0.5 $ ( 106.2 ) $ ( 104.7 ) Other comprehensive (loss) income before reclassifications, 0.1 , ($ 1.0 ), - and ($ 0.9 ) ( 1.2 ) 3.3 - 2.1 Amounts reclassified from accumulated other - ( 2.6 ) ( 1.3 ) ( 3.9 ) Net current period other comprehensive (loss) income ( 1.2 ) 0.7 ( 1.3 ) ( 1.8 ) Balance, June 30, 2024 $ ( 0.2 ) $ 1.2 $ ( 107.5 ) $ ( 106.5 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, March 31, 2023 $ 0.4 $ 7.3 $ ( 109.9 ) $ ( 102.2 ) Other comprehensive income (loss) before reclassifications, - , ($ 0.5 ), $ 0.1 and $( 0.4 ) 0.7 2.1 ( 0.1 ) 2.7 Amounts reclassified from accumulated other - ( 2.3 ) - ( 2.3 ) Net current period other comprehensive income (loss) 0.7 ( 0.2 ) ( 0.1 ) 0.4 Balance, June 30, 2023 $ 1.1 $ 7.1 $ ( 110.0 ) $ ( 101.8 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, December 31, 2022 $ 0.5 $ 9.5 $ ( 110.1 ) $ ( 100.1 ) Other comprehensive income before reclassifications, - , ($ 0.3 ), ($ 0.1 ) and $( 0.4 ) 0.6 1.8 0.3 2.7 Amounts reclassified from accumulated other - ( 4.2 ) ( 0.2 ) ( 4.4 ) Net current period other comprehensive income (loss) 0.6 ( 2.4 ) 0.1 ( 1.7 ) Balance, June 30, 2023 $ 1.1 $ 7.1 $ ( 110.0 ) $ ( 101.8 ) (1) Amounts are net of tax. Amounts Affected Line Item in the Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Derivative Adjustments: Interest rate swap contracts, before tax $ ( 1.2 ) $ ( 2.9 ) $ ( 3.3 ) $ ( 5.3 ) Interest expense Tax impact 0.3 0.6 0.7 1.1 Income tax expense Total (income), net of tax ( 0.9 ) ( 2.3 ) ( 2.6 ) ( 4.2 ) Pension and Postretirement Adjustments: Amortization of prior service credit - ( 0.1 ) ( 0.1 ) ( 0.1 ) Other non-operating (income), net Amortization of net actuarial (gain) ( 0.8 ) - ( 1.6 ) ( 0.2 ) Other non-operating (income), net Total (income), before tax ( 0.8 ) ( 0.1 ) ( 1.7 ) ( 0.3 ) Tax impact 0.1 0.1 0.4 0.1 Income tax expense Total (income), net of tax ( 0.7 ) - ( 1.3 ) ( 0.2 ) Total reclassifications for the period $ ( 1.6 ) $ ( 2.3 ) $ ( 3.9 ) $ ( 4.4 )

Litigation and Related Matters

Litigation and Related Matters	6 Months Ended
	Jun. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Litigation and Related Matters	NOTE 18. LITIGATION AND RELATED MATTERS ENVIRONMENTAL MATTERS Environmental Compliance Our manufacturing and research facilities are affected by various federal, state and local requirements relating to the discharge of materials and the protection of the environment. We make expenditures necessary for compliance with applicable environmental requirements at each of our operating facilities. While these expenditures are not typically material, the applicable regulatory requirements continually change and, as a result, we cannot predict with certainty the amount, nature or timing of future expenditures associated with environmental compliance. Environmental Sites Summary We are actively involved in the investigation and remediation of existing or potential environmental contamination under the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”) and state Superfund and similar environmental laws at two domestically owned locations allegedly resulting from past industrial activity. In each location, we are one of multiple potentially responsible parties and have agreed to jointly fund the required investigation and remediation, while preserving our defenses to the liability. We may also have rights of contribution or reimbursement from other parties or coverage under applicable insurance policies. We have pursued coverage and recoveries under those applicable insurance policies with respect to certain of the sites, including the Macon, Georgia site and the Elizabeth City, North Carolina site, each of which is summarized below. Other than disclosed below, we are unable to predict the outcome of these matters or the timing of any future recoveries, whether through settlement or otherwise. We are also unable to predict the extent to which any recoveries might cover our final share of investigation and remediation costs for these sites. Our final share of investigation and remediation costs may exceed any such recoveries, and such amounts net of insurance recoveries may be material. Between 2017 and 2021, we entered settlement agreements totaling $ 53.0 million with certain legacy insurance carriers to resolve ongoing litigation and recover fees and costs previously incurred by us in connection with certain environmental sites. These settlements were recorded as reductions to cost of goods sold and SG&A expenses, reflecting the same income statement categories where environmental expenditures were historically recorded. From 2020 through the second quarter of 2024, cumulative insurance recoveries exceeded cumulative expenses to date related to the respective environmental sites and the excess was recorded within long-term liabilities on our Condensed Consolidated Balance Sheets. Excess recoveries are released to offset additional reserves for potential liabilities incurred on the respective environmental sites. As of December 31, 2023, insurance recoveries in excess of cumulative expenses were $ 2.6 million. We may enter into additional settlement agreements in the future, which may or may not be material, with other legacy insurers to obtain reimbursement or contribution for environmental site expenses. Estimates of our future liability at the environmental sites are based on evaluations of currently available facts regarding each individual site. We consider factors such as our activities associated with the site, existing technology, presently enacted laws and regulations and prior company experience in remediating contaminated sites. Although current law imposes joint and several liability on all parties at Superfund sites, our contribution to the remediation of these sites is expected to be limited by the number of other companies potentially liable for site remediation. As a result, our estimated liability reflects only our expected share. In determining the probability of contribution, we consider the solvency of other parties, the site activities of other parties, whether liability is being disputed, the terms of any existing agreements and experience with similar matters, and the effect of our October 2006 Chapter 11 reorganization upon the validity of the claim, if any. Specific Material Events Macon, Georgia The U.S. Environmental Protection Agency (the “EPA”) has listed two landfills located on a portion of our facility in Macon, Georgia, along with the former Macon Naval Ordnance Plant landfill adjacent to our property, portions of Rocky Creek, and certain tributaries leading to Rocky Creek (collectively, the “Macon Site”) as a Superfund site on the National Priorities List due to the presence of contaminants, most notably polychlorinated biphenyls (“PCBs”). In September 2010, we entered into an Administrative Order on Consent for a Removal Action (the “Removal Action”) with the EPA to investigate PCB contamination in one of the landfills on our property, the Wastewater Treatment Plant Landfill (“Operable Unit 1”). After completing an investigation of Operable Unit 1 and submitting our final Engineering Evaluation/Cost Analysis, the EPA issued an Action Memorandum in July 2013 selecting our recommended remedy for the Removal Action. The Operable Unit 1 response action is complete and the final report was submitted to the EPA in October 2016 . The EPA approved the final report in November 2016, and a Post-Removal Control Plan was submitted to the EPA in March 2017. AWI has been conducting operation and maintenance activities of the completed remedy since 2017 consistent with the approved Post-Removal Control Plan. In September 2015, AWI and other Potential Responsible Parties (“PRPs”) received a Special Notice Letter from the EPA under CERCLA inviting AWI and the PRPs to enter into the negotiation of a Remedial Investigation and Feasibility Study (“RI/FS”) with respect to the remainder of the Superfund site, which included the other landfill on our property, as well as areas on and adjacent to our property and Rocky Creek (“Operable Unit 2”). We and the other PRPs entered into a settlement agreement with the EPA effective September 2018, in response to the Special Notice Letter to conduct the RI/FS. The PRPs submitted an RI/FS work plan, which was approved by the EPA in September 2019. Investigative work on this portion of the site commenced in December 2019. In June 2021, the PRPs submitted a Site Characterization Summary Report (“SCSR”) for Operable Unit 2 to the EPA. The purpose of the SCSR was to demonstrate that the available data for Operable Unit 2 was adequate for the risk assessment and for the development of remedial action objectives. In the second half of 2022, the EPA and the PRP's agreed to separate all non-groundwater aspects of the site. In August 2022, the PRPs submitted a Human Health Baseline Risk Assessment to the EPA, and in December 2022, the PRPs submitted a final Baseline Ecological Risk Assessment for all non-groundwater aspects of Operable Unit 2 to the EPA. Both risk assessments served as exhibits to the Remedial Investigation Report (“RIR”), which the EPA approved in July 2023. Based on findings in the RIR, the PRPs developed a draft Feasibility Study (“FS”) to identify and evaluate potential remedial alternatives for all non-groundwater elements of Operable Unit 2. The draft FS was submitted to the EPA in August 2023. The EPA and the State of Georgia provided comments in October 2023 and a revised FS was submitted in November 2023. The EPA conditionally approved the FS in April 2024 and issued a Proposed Remedial Action Plan (“Proposed Plan”) for the non-groundwater elements at the site in May 2024. The EPA held a public meeting in May 2024 to explain the Proposed Plan and start the thirty-day period for public comment, which closed on June 30, 2024. The EPA will review any public comments and then issue a Record of Decision, officially selecting the remedy to be implemented. The EPA’s Proposed Plan included a total cost estimate for the non-groundwater elements at the site of approximately $ 8 million. The portion of these remediation costs that AWI will bear for all non-groundwater elements of Operable Unit 2 will not be known until the PRPs resolve the final allocation of costs. It is probable that we will incur field investigation, engineering and oversight costs associated with designing and implementing the remedy for all non-groundwater elements of Operable Unit 2 and for completing an RI/FS for all groundwater elements of Operable Unit 2 (“Operable Unit 3”). We may also ultimately incur costs in remediating contamination discovered during the RI/FS for Operable Unit 3 and we are unable to reasonably estimate our final share of the total costs associated with the investigation work or any resulting remediation therefrom, although such amounts may be material to any one quarter's or year's results of operations in the future. We do not expect the total future costs to have a material adverse effect on our liquidity or financial condition as the cash payments may be made over many years. Elizabeth City, North Carolina This site is a former cabinet manufacturing facility that from 1977 until 1996 was operated by Triangle Pacific Corporation, which became Armstrong Wood Products, Inc. (“AWP”), and is now known as AHF Products, LLC. The site was formerly owned by the U.S. Navy (“Navy”) and Westinghouse, which was purchased by Paramount Global (“Paramount”) (then known as CBS Corporation). We assumed ownership of the site when we acquired the stock of AWP in 1998. Prior to our acquisition, the North Carolina Department of Environment and Natural Resources listed the site as a hazardous waste site. In 1997, AWP entered into a cost sharing agreement with Westinghouse whereby the parties agreed to share equally in costs associated with investigation and potential remediation. In 2000, AWP and Paramount entered into an Administrative Order on Consent to conduct an RI/FS with the EPA for the site. In 2007, we and Paramount entered into an agreement with the Navy whereby the Navy agreed to pay one third of defined past and future investigative costs up to a certain amount, which has now been exhausted. The EPA approved the RI/FS work plan in August 2011. In January 2014, we submitted draft RI and Risk Assessment reports and conducted supplemental investigative work based upon agency comments to those reports. In connection with the separation of Armstrong Flooring, Inc. in 2016, we agreed to retain any legacy environmental liabilities associated with the AWP site. The EPA published an Interim Action Proposed Plan for the site in April 2018 seeking public comment until June 2018. The EPA evaluated comments, including ours, and has published its Interim Record Of Decision (“IROD”) selecting an interim cleanup approach. In September 2018, AWI and Paramount received a Special Notice Letter from the EPA under CERCLA inviting AWI and Paramount to enter into the negotiation of a settlement agreement to conduct or finance the response action at the site. In response to the September 2018 Special Notice Letter, we and Paramount submitted a good faith offer to the EPA in May 2019. In June 2021, we entered into a negotiated Partial Consent Decree and Site Participation Agreement with the EPA, Paramount and the U.S. on behalf of the Navy for the remedial design and remedial action for the interim remedy. Because the U.S. does not conduct work as a PRP at Superfund sites, similar to the 2007 agreement, the U.S. agreed to pay its share of the estimated costs of performing the work. The Partial Consent Decree was entered by the U.S. District Court for the Eastern District of North Carolina in January 2022. A Remedial Design Work Plan (“RDWP”) for the site was submitted to the EPA in June 2022, and AWI and Paramount responded on November 2022 to comments received from the EPA in September 2022. The EPA approved the revised RDWP in February 2023 and in June 2023, the parties submitted a Pre-Design Investigation Work Plan. The EPA provided comments on the Pre-Design Investigation Work Plan in November 2023 and the revised document was submitted to the EPA in December 2023. In March 2024, the EPA issued a conditional approval of the Pre-Design Investigation Work Plan, subject to the Company and Paramount addressing the EPA comments on a component of the Work Plan within 60 days. In May 2024, AWI submitted a revised Pre-Design Investigation Work Plan to address additional comments received from the EPA. The current estimate of future liability at this site includes only our estimated share of the costs of implementing the interim remedial action under the IROD. We are unable to reasonably estimate our final share of the total costs associated with the interim or final remediation at the site, although such amounts may be material to any one quarter's or one year’s results of operations in the future. We do not expect the total future costs to have a material adverse effect on our liquidity or financial condition as the cash payments may be made over many years. Summary of Financial Position Total liabilities, reflected within other long-term liabilities on the Condensed Consolidated Balance Sheets, for environmental matters that we consider probable and for which a reasonable estimate of the probable liability could be made were $ 4.2 million and $ 0.5 million as of June 30, 2024 and December 31, 2023 , respectively. As noted above, expenses associated with additional reserves for environmental matters were offset through the release of a portion of the balance of insurance recoveries in excess of cumulative expenses. During the three and six months ended June 30, 2024, we recorded $ 4.0 million of additional reserves for potential environmental liabilities, of which, $ 2.5 million was offset through a release of our remaining environmental insurance recoveries in excess of cumulative expenses, and $ 1.5 million was recorded as a component of SG&A expenses on our Condensed Consolidated Statements of Earnings and Comprehensive Income. We did not record any additional reserves for potential environmental liabilities during the three and six months ended June 30, 2023. Where existing data is sufficient to estimate the liability, that estimate has been used; where only a range of probable liabilities is available and no amount within that range is more likely than any other, the lower end of the range has been used. As assessments and remediation activities progress at each site, these liabilities are reviewed to reflect new information as it becomes available and adjusted to reflect amounts actually incurred and paid. These liabilities are undiscounted. The estimated environmental liabilities above do not take into account any claims for additional recoveries from insurance or third parties. It is our policy to record insurance recoveries as assets in the Condensed Consolidated Balance Sheets when realizable. We incur costs to pursue environmental insurance recoveries, which are expensed as incurred. Actual costs to be incurred at identified sites may vary from our estimates. Based on our knowledge of the identified sites, it is not possible to reasonably estimate future costs in excess of amounts already recognized. OTHER CLAIMS From time to time, we are involved in other various lawsuits, claims, investigations and other legal matters that arise in the ordinary course of business, including matters involving our products, intellectual property, relationships with suppliers, relationships with distributors, other customers or end users, relationships with competitors, employees and other matters. In connection with those matters, we may have rights of indemnity, contribution or reimbursement from other parties or coverage under applicable insurance policies. When applicable and appropriate, we will seek indemnity, contribution or reimbursement from other parties and pursue coverage and recoveries under those policies, but are unable to predict the outcome of those demands. While complete assurance cannot be given to the outcome of any proceedings relating to these matters, we do not believe that any current claims, individually or in the aggregate, will have a material adverse effect on our financial condition, liquidity or results of operations.

Net Earnings Per Share

Net Earnings Per Share	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Net Earnings Per Share	NOTE 19. NET EARNINGS PER SHARE The following table is a reconciliation of net earnings attributable to common shares used in our basic and diluted net Earnings Per Share (“EPS”) calculations for the three and six months ended June 30, 2024 and 2023. EPS components may not add due to rounding. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net earnings $ 65.9 $ 60.2 $ 125.8 $ 107.5 (Earnings) allocated to participating vested share awards - - - ( 0.1 ) Net earnings attributable to common shares $ 65.9 $ 60.2 $ 125.8 $ 107.4 The following table is a reconciliation of basic shares outstanding to diluted shares outstanding for the three and six months ended June 30, 2024 and 2023 (shares in millions): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Basic shares outstanding 43.8 44.9 43.8 45.2 Dilutive effect of common stock equivalents 0.2 0.1 0.2 - Diluted shares outstanding 44.0 45.0 44.0 45.2 There were no anti-dilutive stock awards excluded from the computation of dilutive EPS for the three months ended June 30, 2024. Anti-dilutive stock awards excluded from the computation of dilutive EPS for the six months ended June 30, 2024 were 17,426 . Anti-dilutive stock awards excluded from the computation of dilutive EPS for the three and six months ended June 30, 2023 were 191,659 and 133,144 , respectively.

Business and Basis of Present_2

Business and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2024
Accounting Policies [Abstract]
Acquisitions	We account for acquisitions under the acquisition method and the results of operations of acquired operations are included in the Condensed Consolidated Financial Statements from the acquisition date. Acquisition related costs are expensed as incurred. We allocate total consideration to the assets acquired and liabilities assumed based on their estimated fair values, with the remaining unallocated amount recorded as goodwill. Definite-lived intangible assets are amortized over the estimated useful life on a straight-line basis and recorded as a component of operating income. The fair value of acquired intangible assets is estimated by applying discounted cash flow models based on significant level 3 inputs not observable in the market. Key assumptions are developed based on each acquirees’ historical experience, future projections and comparable market data including future cash flows, long-term growth rates, implied royalty rates, attrition rates and discount rates. Acquisition-related contingent consideration that is classified as a liability is measured at fair value as of the acquisition date. The fair value of contingent consideration is remeasured at each reporting period, and any future changes in the fair value of contingent consideration recorded in reporting periods after the acquisition date are recorded within loss related to change in fair value of contingent consideration on our Condensed Consolidated Statements of Earnings and Comprehensive Income.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, “Improvements to Reportable Segment Disclosures,” which modifies reportable segment disclosure requirements. This ASU expands annual and interim reportable segment disclosures, including: disclosure of the title and position of our chief operating decision maker (“CODM”), interim and annual disclosure of significant reportable segment expenses that are components of segment profit or loss information provided to the CODM, and interim disclosure of all annual reportable segment profit or loss and asset data currently only required to be disclosed annually. This guidance is effective for annual periods beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. The adoption of this standard is not expected to have an impact on our financial statements, but will result in significantly expanded reportable segment disclosures. In December 2023, the FASB issued ASU 2023-09, “Improvements to Income Tax Disclosures,” which modifies the disclosure requirements for income taxes. This ASU requires disclosure of tabular statutory to effective rate reconciliation in both percentages and dollars, additional disaggregated rate reconciliation categories and disaggregation of both income taxes paid and income tax expense by jurisdiction. This guidance is effective for annual periods beginning after December 15, 2024. We expect this ASU to only impact our disclosures with no impact to our result of operations, cash flows and financial condition.

Segment Results (Tables)

Segment Results (Tables)	6 Months Ended
	Jun. 30, 2024
Segment Reporting [Abstract]
Schedule of Net Sales	Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales Mineral Fiber $ 250.2 $ 234.0 $ 489.8 $ 462.4 Architectural Specialties 114.9 91.4 201.6 173.2 Total net sales $ 365.1 $ 325.4 $ 691.4 $ 635.6
Reconciliation of Total Consolidated Operating Income to Earnings Before Income Taxes	Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Segment operating income (loss) Mineral Fiber $ 81.7 $ 75.5 $ 160.9 $ 139.3 Architectural Specialties 14.2 12.2 21.9 19.4 Unallocated Corporate ( 0.9 ) ( 0.7 ) ( 1.7 ) ( 1.5 ) Total consolidated operating income $ 95.0 $ 87.0 $ 181.1 $ 157.2
Schedule of Segment Operating Income (Loss)	Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Total consolidated operating income $ 95.0 $ 87.0 $ 181.1 $ 157.2 Interest expense 11.1 9.2 20.1 17.9 Other non-operating (income), net ( 3.2 ) ( 2.2 ) ( 6.3 ) ( 4.6 ) Earnings before income taxes $ 87.1 $ 80.0 $ 167.3 $ 143.9
Reconciliation of Total Segment Assets to Total Consolidated Assets	June 30, 2024 December 31, 2023 Segment assets Mineral Fiber $ 1,098.1 $ 1,091.9 Architectural Specialties 549.6 421.1 Unallocated Corporate 172.5 159.4 Total consolidated assets $ 1,820.2 $ 1,672.4

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2024
Mineral Fiber [Member]
Disaggregation Of Revenue [Line Items]
Schedule of Net Sales by Major Customer Channel within Each Segment	The following tables provide net sales by major customer channel within our Mineral Fiber and Architectural Specialties segments for the three and six months ended June 30, 2024 and 2023: Three Months Ended Six Months Ended June 30, June 30, Mineral Fiber 2024 2023 2024 2023 Distributors $ 184.9 $ 174.6 $ 354.2 $ 334.4 Home centers 24.5 23.4 55.5 54.5 Direct customers 16.6 15.2 29.7 29.9 Other 24.2 20.8 50.4 43.6 Total $ 250.2 $ 234.0 $ 489.8 $ 462.4
Architectural Specialties [Member]
Disaggregation Of Revenue [Line Items]
Schedule of Net Sales by Major Customer Channel within Each Segment	Three Months Ended Six Months Ended June 30, June 30, Architectural Specialties 2024 2023 2024 2023 Distributors $ 55.5 $ 45.9 $ 109.3 $ 85.1 Direct customers 53.7 44.4 83.7 86.4 Other 5.7 1.1 8.6 1.7 Total $ 114.9 $ 91.4 $ 201.6 $ 173.2

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2024
Business Acquisition [Line Items]
Schedule of Business Acquisitions	The following table summarizes aggregate unaudited as reported and pro forma information assuming the acquisition of 3form had occurred on January 1, 2023. The unaudited pro forma results include the depreciation and amortization associated with the acquired assets. The unaudited pro forma results do not include any expected benefits from the 3form acquisition. Accordingly, the unaudited pro forma results are not necessarily indicative of either future results of operations or results that might have been achieved had the acquisition been consummated as of January 1, 2023. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales, pro forma $ 388.3 $ 348.0 $ 737.7 $ 683.9 Net sales, as reported 365.1 325.4 691.4 635.6 Earnings before income taxes, pro forma 89.8 79.4 170.2 143.4 Earnings before income taxes, as reported 87.1 80.0 167.3 143.9 For the three and six months ended June 30, 2024, net sales of $ 20.4 and $ 23.4 , respectively, from BOK and 3form were included in our Condensed Consolidated Statements of Operations and Comprehensive Income since the acquisition dates.
3form [Member]
Business Acquisition [Line Items]
Schedule of Fair Values of Identifiable Intangible Assets Acquired and Estimated Useful Lives	The following table summarizes the fair values of identifiable intangible assets acquired, and their estimated useful lives: Fair Value at Acquisition Date Estimated Useful Life Customer relationships $ 16.6 5 years Trademarks and brand names 15.0 15 years Non-compete agreements 3.8 5 years Software 1.9 5 years Backlog 1.2 1 year Developed technology 1.1 16 years Total identifiable intangible assets $ 39.6

Accounts and Notes Receivable (

Accounts and Notes Receivable (Tables)	6 Months Ended
	Jun. 30, 2024
Receivables [Abstract]
Schedule of Accounts and Notes Receivable	June 30, 2024 December 31, 2023 Customer receivables $ 130.3 $ 102.1 Miscellaneous receivables 9.5 11.8 Less allowance for warranties, discounts and losses ( 3.8 ) ( 2.9 ) Accounts and notes receivable, net $ 136.0 $ 111.0

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Jun. 30, 2024
Inventory Disclosure [Abstract]
Schedule of Inventories	June 30, 2024 December 31, 2023 Finished goods $ 60.7 $ 55.1 Goods in process 7.2 5.1 Raw materials and supplies 71.6 66.7 Less LIFO reserves ( 25.7 ) ( 22.9 ) Total inventories, net $ 113.8 $ 104.0

Other Current Assets (Tables)

Other Current Assets (Tables)	6 Months Ended
	Jun. 30, 2024
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Current Assets	June 30, 2024 December 31, 2023 Prepaid expenses $ 15.2 $ 15.9 Assets held for sale 4.6 6.7 Fair value of derivative assets 1.5 1.1 Other 2.5 2.7 Total other current assets $ 23.8 $ 26.4

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	6 Months Ended
	Jun. 30, 2024
Schedule of Equity Method Investments [Line Items]
Summary of Investment in Joint Venture, Income Statement Data	Condensed financial statement data for WAVE is summarized below. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net sales $ 126.1 $ 116.1 $ 251.9 $ 225.6 Gross profit 71.1 70.1 147.8 132.4 Net earnings 55.2 51.6 112.2 95.4
Schedule of Equity (Earnings) Losses from Unconsolidated Affiliates	The following table presents equity (earnings) losses from our unconsolidated affiliates for the three and six months ended June 30, 2024 and 2023: Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 WAVE $ ( 26.5 ) $ ( 24.9 ) $ ( 53.9 ) $ ( 45.7 ) Overcast 0.2 - 0.4 - Equity (earnings) from unconsolidated affiliates, net $ ( 26.3 ) $ ( 24.9 ) $ ( 53.5 ) $ ( 45.7 )

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Intangible Assets	The following table details amounts related to our goodwill and intangible assets as of June 30, 2024 and December 31, 2023: June 30, 2024 December 31, 2023 Estimated Gross Accumulated Amortization Gross Accumulated Amortization Amortizing intangible assets Customer relationships 2 - 20 years $ 200.1 $ 157.9 $ 183.6 $ 152.1 Developed technology 13 - 20 years 103.1 85.0 101.4 84.4 Software 5 - 7 years 17.5 6.0 15.6 4.6 Trademarks and brand names 3 - 20 years 21.2 3.8 6.2 3.4 Non-compete agreements 3 - 5 years 9.7 4.4 6.1 3.8 Other Various 4.0 0.4 2.8 0.2 Total $ 355.6 $ 257.5 $ 315.7 $ 248.5 Non-amortizing intangible assets Trademarks and brand names Indefinite 345.3 345.2 Total intangible assets $ 700.9 $ 660.9 Goodwill Indefinite $ 193.8 $ 175.5 The net increase in goodwill as of June 30, 2024 compared to December 31, 2023 was due to the acquisition of 3form, net of foreign exchange movements. Six Months Ended June 30, 2024 2023 Amortization expense $ 9.4 $ 7.1

Other Non-Current Assets (Table

Other Non-Current Assets (Tables)	6 Months Ended
	Jun. 30, 2024
Other Assets, Noncurrent Disclosure [Abstract]
Schedule of Other Non-Current Assets	June 30, 2024 December 31, 2023 Cash surrender value of company-owned life insurance policies $ 37.9 $ 40.3 Investment in employee deferred compensation plans 12.4 8.3 Fair value of derivative assets 0.3 1.8 Other 1.2 0.9 Total other non-current assets $ 51.8 $ 51.3

Accounts Payable And Accrued _2

Accounts Payable And Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2024
Payables and Accruals [Abstract]
Schedule of Accounts Payable and Accrued Expenses	June 30, 2024 December 31, 2023 Payables, trade and other $ 106.4 $ 91.0 Employment costs 21.2 33.6 Current portion of pension and postretirement liabilities 8.0 8.0 Other 27.4 27.3 Total accounts payable and accrued expenses $ 163.0 $ 159.9

Income Tax Expense (Tables)

Income Tax Expense (Tables)	6 Months Ended
	Jun. 30, 2024
Income Tax Disclosure [Abstract]
Schedule of Income Tax Expense	Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Earnings before income taxes $ 87.1 $ 80.0 $ 167.3 $ 143.9 Income tax expense 21.2 19.8 41.5 36.4 Effective tax rate 24.3 % 24.8 % 24.8 % 25.3 %

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2024
Letter of Credit [Member]
Debt Instrument [Line Items]
Schedule of Letters of Credit Facilities	The following table presents details related to our letters of credit facilities: June 30, 2024 Financing Arrangements Limit Used Available Bi-lateral facility $ 25.0 $ 7.4 $ 17.6 Revolving credit facility 150.0 - 150.0 Total $ 175.0 $ 7.4 $ 167.6

Pensions and Other Benefit Pr_2

Pensions and Other Benefit Programs (Tables)	6 Months Ended
	Jun. 30, 2024
Retirement Benefits [Abstract]
Schedule of Periodic Benefit Costs (Credits)	Following are the components of net periodic benefit costs (credits): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 U.S. defined benefit plans: Pension benefits Service cost of benefits earned during the period $ 0.6 $ 0.6 $ 1.2 $ 1.3 Interest cost on projected benefit obligation 4.2 4.3 8.4 8.5 Expected return on plan assets ( 6.1 ) ( 6.3 ) ( 12.2 ) ( 12.5 ) Amortization of net actuarial loss 1.3 1.4 2.6 2.7 Net periodic pension cost $ - $ - $ - $ - Retiree health and life insurance benefits Interest cost on projected benefit obligation $ 0.5 $ 0.7 $ 1.0 $ 1.4 Amortization of prior service credit - ( 0.1 ) ( 0.1 ) ( 0.1 ) Amortization of net actuarial gain ( 2.1 ) ( 1.4 ) ( 4.2 ) ( 2.9 ) Net periodic postretirement credit $ ( 1.6 ) $ ( 0.8 ) $ ( 3.3 ) $ ( 1.6 )

Financial Instruments and Con_2

Financial Instruments and Contingent Consideration (Tables)	6 Months Ended
	Jun. 30, 2024
Fair Value Disclosures [Abstract]
Estimated Fair Value of Financial Instruments	The estimated fair values of our financial instruments and contingent consideration are as follows: June 30, 2024 December 31, 2023 Carrying Estimated Carrying Estimated Assets (liabilities), net: Total long-term debt, including current portion $ ( 644.0 ) $ ( 644.0 ) $ ( 586.8 ) $ ( 586.8 ) Interest rate swap contracts 1.3 1.3 ( 0.4 ) ( 0.4 ) Acquisition-related contingent consideration ( 2.0 ) ( 2.0 ) ( 1.6 ) ( 1.6 )
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The fair value measurement of assets and liabilities measured at fair value on a recurring basis and reported on the Condensed Consolidated Balance Sheets is summarized below: June 30, 2024 December 31, 2023 Fair value based on Fair value based on Other Other Other Other Level 2 Level 3 Level 2 Level 3 Assets (liabilities), net: Interest rate swap contracts $ 1.3 $ - $ ( 0.4 ) $ - Acquisition-related contingent consideration - ( 2.0 ) - ( 1.6 )
Schedule of Weighted-average Of Significant Unobservable Inputs	The following table summarizes the weighted-average of the significant unobservable inputs as o f June 30, 2024: BOK Insolcorp Unobservable input Volatility 23.2 % 21.2 % Discount rates 5.1 % 5.1 %
Schedule of Changes in Fair Value of the Acquisition-related Contingent Consideration Liability	The changes in fair value of the acquisition-related contingent consideration liabilities for the three months ended June 30, 2024 and the six months ended June 30, 2024 and 2023 were as follows: Three Months Ended Six Months Ended June 30, June 30, 2024 2024 2023 Fair value of contingent consideration as of beginning of period $ 1.3 $ 1.6 $ 15.2 Cash consideration paid - - ( 15.2 ) Loss related to change in fair value of contingent consideration 0.7 0.4 - Fair value of contingent consideration as of end of period $ 2.0 $ 2.0 $ -

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Interest Rate Swaps	The following table summarizes our interest rate swaps as of June 30, 2024: Coverage Period Notional Risk Coverage Trade Date March 2021 to March 2025 $ 100.0 USD-SOFR November 28, 2018 November 2023 to December 2025 $ 50.0 USD-SOFR October 23, 2023 March 2024 to June 2026 $ 50.0 USD-SOFR March 25, 2024 November 2023 to December 2026 $ 50.0 USD-SOFR October 10, 2023 March 2024 to June 2027 $ 50.0 USD-SOFR March 27, 2024 November 2023 to November 2027 $ 50.0 USD-SOFR September 29, 2023 June 2024 to June 2028 $ 50.0 USD-SOFR June 26, 2024
Summary of Fair Value of Derivative Instruments on Consolidated Balance Sheet	Derivative Assets Derivative Liabilities Fair Value Fair Value Balance Sheet June 30, December 31, Balance Sheet June 30, December 31, Interest rate swap contracts Other current assets $ 1.5 $ 1.1 Accounts payable and accrued expenses $ - $ 0.1 Interest rate swap contracts Other non-current assets 0.3 1.8 Other long-term liabilities 0.5 3.2
Summary of Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	Amount of Gain Location of Gain Reclassified from Gain Reclassified Six Months Ended Three Months Ended Six Months Ended June 30, June 30, June 30, 2024 2023 2024 2023 2024 2023 Derivatives in cash flow hedging relationships Interest rate swap contracts $ 4.3 $ 2.1 Interest expense $ 1.2 $ 2.9 $ 3.3 $ 5.3

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2024
Stockholders' Equity Note [Abstract]
Schedule of Accumulated Other Comprehensive (Loss) Activity	Accumulated Other Comprehensive (Loss) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, March 31, 2024 $ 0.2 $ 1.0 $ ( 106.8 ) $ ( 105.6 ) Other comprehensive (loss) income before reclassifications, - , ($ 0.3 ), - and ($ 0.3 ) ( 0.4 ) 1.1 - 0.7 Amounts reclassified from accumulated other - ( 0.9 ) ( 0.7 ) ( 1.6 ) Net current period other comprehensive (loss) income ( 0.4 ) 0.2 ( 0.7 ) ( 0.9 ) Balance, June 30, 2024 $ ( 0.2 ) $ 1.2 $ ( 107.5 ) $ ( 106.5 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, December 31, 2023 $ 1.0 $ 0.5 $ ( 106.2 ) $ ( 104.7 ) Other comprehensive (loss) income before reclassifications, 0.1 , ($ 1.0 ), - and ($ 0.9 ) ( 1.2 ) 3.3 - 2.1 Amounts reclassified from accumulated other - ( 2.6 ) ( 1.3 ) ( 3.9 ) Net current period other comprehensive (loss) income ( 1.2 ) 0.7 ( 1.3 ) ( 1.8 ) Balance, June 30, 2024 $ ( 0.2 ) $ 1.2 $ ( 107.5 ) $ ( 106.5 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, March 31, 2023 $ 0.4 $ 7.3 $ ( 109.9 ) $ ( 102.2 ) Other comprehensive income (loss) before reclassifications, - , ($ 0.5 ), $ 0.1 and $( 0.4 ) 0.7 2.1 ( 0.1 ) 2.7 Amounts reclassified from accumulated other - ( 2.3 ) - ( 2.3 ) Net current period other comprehensive income (loss) 0.7 ( 0.2 ) ( 0.1 ) 0.4 Balance, June 30, 2023 $ 1.1 $ 7.1 $ ( 110.0 ) $ ( 101.8 ) Foreign (1) Derivative (1) Pension and Postretirement Adjustments (1) Total (1) Balance, December 31, 2022 $ 0.5 $ 9.5 $ ( 110.1 ) $ ( 100.1 ) Other comprehensive income before reclassifications, - , ($ 0.3 ), ($ 0.1 ) and $( 0.4 ) 0.6 1.8 0.3 2.7 Amounts reclassified from accumulated other - ( 4.2 ) ( 0.2 ) ( 4.4 ) Net current period other comprehensive income (loss) 0.6 ( 2.4 ) 0.1 ( 1.7 ) Balance, June 30, 2023 $ 1.1 $ 7.1 $ ( 110.0 ) $ ( 101.8 ) (1) Amounts are net of tax.
Reclassification out of Accumulated Other Comprehensive (Loss)	Amounts Affected Line Item in the Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Derivative Adjustments: Interest rate swap contracts, before tax $ ( 1.2 ) $ ( 2.9 ) $ ( 3.3 ) $ ( 5.3 ) Interest expense Tax impact 0.3 0.6 0.7 1.1 Income tax expense Total (income), net of tax ( 0.9 ) ( 2.3 ) ( 2.6 ) ( 4.2 ) Pension and Postretirement Adjustments: Amortization of prior service credit - ( 0.1 ) ( 0.1 ) ( 0.1 ) Other non-operating (income), net Amortization of net actuarial (gain) ( 0.8 ) - ( 1.6 ) ( 0.2 ) Other non-operating (income), net Total (income), before tax ( 0.8 ) ( 0.1 ) ( 1.7 ) ( 0.3 ) Tax impact 0.1 0.1 0.4 0.1 Income tax expense Total (income), net of tax ( 0.7 ) - ( 1.3 ) ( 0.2 ) Total reclassifications for the period $ ( 1.6 ) $ ( 2.3 ) $ ( 3.9 ) $ ( 4.4 )

Net Earnings Per Share (Tables)

Net Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2024
Earnings Per Share [Abstract]
Reconciliation of Net Earnings Attributable to Common Shares Used in Basic and Diluted Net Earnings Per Share Calculation	The following table is a reconciliation of net earnings attributable to common shares used in our basic and diluted net Earnings Per Share (“EPS”) calculations for the three and six months ended June 30, 2024 and 2023. EPS components may not add due to rounding. Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Net earnings $ 65.9 $ 60.2 $ 125.8 $ 107.5 (Earnings) allocated to participating vested share awards - - - ( 0.1 ) Net earnings attributable to common shares $ 65.9 $ 60.2 $ 125.8 $ 107.4
Reconciliation of Basic Shares Outstanding to Diluted Shares Outstanding	The following table is a reconciliation of basic shares outstanding to diluted shares outstanding for the three and six months ended June 30, 2024 and 2023 (shares in millions): Three Months Ended Six Months Ended June 30, June 30, 2024 2023 2024 2023 Basic shares outstanding 43.8 44.9 43.8 45.2 Dilutive effect of common stock equivalents 0.2 0.1 0.2 - Diluted shares outstanding 44.0 45.0 44.0 45.2

Business and Basis of Present_3

Business and Basis of Presentation (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Jan. 31, 2024	Jun. 30, 2024
WAVE [Member]
Business And Basis Of Presentation [Line Items]
Equity interest percentage		50%
Overcast [Member]
Business And Basis Of Presentation [Line Items]
Investment in strategic partnership	$ 5.5
Equity interest percentage	19.50%	19.50%

Segment Results (Schedule of Ne

Segment Results (Schedule of Net Sales) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total net sales	$ 365.1	$ 325.4	$ 691.4	$ 635.6
Mineral Fiber [Member]
Segment Reporting Information [Line Items]
Total net sales	250.2	234	489.8	462.4
Architectural Specialties [Member]
Segment Reporting Information [Line Items]
Total net sales	$ 114.9	$ 91.4	$ 201.6	$ 173.2

Segment Results (Reconciliation

Segment Results (Reconciliation of Total Consolidated Operating Income to Earnings Before Income Taxes) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total Consolidated Operating Income (Loss)	$ 95	$ 87	$ 181.1	$ 157.2
Mineral Fiber [Member]
Segment Reporting Information [Line Items]
Total Consolidated Operating Income (Loss)	81.7	75.5	160.9	139.3
Architectural Specialties [Member]
Segment Reporting Information [Line Items]
Total Consolidated Operating Income (Loss)	14.2	12.2	21.9	19.4
Unallocated Corporate [Member]
Segment Reporting Information [Line Items]
Total Consolidated Operating Income (Loss)	$ (0.9)	$ (0.7)	$ (1.7)	$ (1.5)

Segment Results (Schedule of Se

Segment Results (Schedule of Segment Operating Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting [Abstract]
Total consolidated operating income	$ 95	$ 87	$ 181.1	$ 157.2
Interest expense	11.1	9.2	20.1	17.9
Other non-operating (income), net	(3.2)	(2.2)	(6.3)	(4.6)
Earnings before income taxes	$ 87.1	$ 80	$ 167.3	$ 143.9

Segment Results (Reconciliati_2

Segment Results (Reconciliation of Total Segment Assets to Total Consolidated Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total consolidated assets	$ 1,820.2	$ 1,672.4
Mineral Fiber [Member]
Segment Reporting Information [Line Items]
Total consolidated assets	1,098.1	1,091.9
Architectural Specialties [Member]
Segment Reporting Information [Line Items]
Total consolidated assets	549.6	421.1
Unallocated Corporate [Member]
Segment Reporting Information [Line Items]
Total consolidated assets	$ 172.5	$ 159.4

Revenue (Schedule of Net Sales

Revenue (Schedule of Net Sales by Major Customer Group within Each Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 365.1	$ 325.4	$ 691.4	$ 635.6
Mineral Fiber [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	250.2	234	489.8	462.4
Mineral Fiber [Member] | Distributors [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	184.9	174.6	354.2	334.4
Mineral Fiber [Member] | Home Centers [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	24.5	23.4	55.5	54.5
Mineral Fiber [Member] | Direct Customers [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	16.6	15.2	29.7	29.9
Mineral Fiber [Member] | Other [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	24.2	20.8	50.4	43.6
Architectural Specialties [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	114.9	91.4	201.6	173.2
Architectural Specialties [Member] | Distributors [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	55.5	45.9	109.3	85.1
Architectural Specialties [Member] | Direct Customers [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	53.7	44.4	83.7	86.4
Architectural Specialties [Member] | Other [Member]
Entity Wide Revenue Major Customer [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 5.7	$ 1.1	$ 8.6	$ 1.7

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended			6 Months Ended
	Apr. 30, 2024	May 31, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 193.8	$ 175.5		$ 193.8
Intangible assets acquired		$ 11
Payments to acquire intangible assets				$ 1	$ 10
Net sales			365.1		$ 325.4	691.4	$ 635.6
3form [Member]
Finite-Lived Intangible Assets [Line Items]
Payments to acquire business	$ 93.9
Business acquisition, cash acquired	0.5
Business acquisition, total fair value of liabilities assumed, less tangible assets acquired	36.3
Business acquisition, accounts receivable	6.9
Business acquisition, inventory	7.9
Business acquisition, property, plant and equipment	37.5
Business acquisition, operating lease assets and liabilities	10
Business acquisition, accounts payable and accrued liabilities	17.5
Fair value of identifiable intangible assets acquired	39.6
Goodwill	18.5
BOK and 3form [Member]
Finite-Lived Intangible Assets [Line Items]
Net sales			20.4			23.4
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of identifiable intangible assets acquired			6.5			$ 6.5
Estimated Useful Life						5 years
Software [Member] | 3form [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of identifiable intangible assets acquired	$ 1.9
Estimated Useful Life	5 years
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of identifiable intangible assets acquired			$ 4.5			$ 4.5
Estimated Useful Life						17 years
Developed Technology [Member] | 3form [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of identifiable intangible assets acquired	$ 1.1
Estimated Useful Life	16 years

Acquisitions (Schedule of Fair

Acquisitions (Schedule of Fair Values of Identifiable Intangible Assets Acquired and Estimated Useful Lives) (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Apr. 30, 2024	Jun. 30, 2024
Software [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date		$ 6.5
Estimated Useful Life		5 years
Developed Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date		$ 4.5
Estimated Useful Life		17 years
3form [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 39.6
3form [Member] | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 16.6
Estimated Useful Life	5 years
3form [Member] | Trademarks And Brand Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 15
Estimated Useful Life	15 years
3form [Member] | Non-compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 3.8
Estimated Useful Life	5 years
3form [Member] | Software [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 1.9
Estimated Useful Life	5 years
3form [Member] | Backlog [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 1.2
Estimated Useful Life	1 year
3form [Member] | Developed Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Fair Value at Acquisition Date	$ 1.1
Estimated Useful Life	16 years

Acquisitions (Schedule of Busin

Acquisitions (Schedule of Business Acquisitions) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Business Acquisition, Pro Forma Information [Abstract]
Net sales, pro forma	$ 388.3	$ 348	$ 737.7	$ 683.9
Net sales, as reported	365.1	325.4	691.4	635.6
Earnings before income taxes, pro forma	89.8	79.4	170.2	143.4
Earnings before income taxes, as reported	$ 87.1	$ 80	$ 167.3	$ 143.9

Accounts and Notes Receivable_2

Accounts and Notes Receivable (Schedule of Accounts and Notes Receivable) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Receivables [Abstract]
Customer receivables	$ 130.3	$ 102.1
Miscellaneous receivables	9.5	11.8
Less allowance for warranties, discounts and losses	(3.8)	(2.9)
Accounts and notes receivable, net	$ 136	$ 111

Inventories (Schedule of Invent

Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Finished goods	$ 60.7	$ 55.1
Goods in process	7.2	5.1
Raw materials and supplies	71.6	66.7
Less LIFO reserves	(25.7)	(22.9)
Total inventories, net	$ 113.8	$ 104

Other Current Assets (Schedule

Other Current Assets (Schedule of Other Current Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 15.2	$ 15.9
Assets held for sale	4.6	6.7
Fair value of derivative assets	1.5	1.1
Other	2.5	2.7
Total other current assets	$ 23.8	$ 26.4

Other Current Assets (Narrative

Other Current Assets (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Proceeds from the sale of assets	$ 2.1

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates (Narrative) (Details)	Jun. 30, 2024	Jan. 31, 2024
WAVE [Member]
Schedule of Equity Method Investments [Line Items]
Equity interest percentage	50%
Overcast [Member]
Schedule of Equity Method Investments [Line Items]
Equity interest percentage	19.50%	19.50%

Investments in Unconsolidated_4

Investments in Unconsolidated Affiliates (Summary of Investment in Joint Venture, Income Statement Data) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Schedule of Equity Method Investments [Line Items]
Net sales	$ 365.1	$ 325.4	$ 691.4	$ 635.6
Gross profit	149.3	124	273.6	236.1
Net earnings	65.9	60.2	125.8	107.5
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] | Partnership Interest Member
Schedule of Equity Method Investments [Line Items]
Net sales	126.1	116.1	251.9	225.6
Gross profit	71.1	70.1	147.8	132.4
Net earnings	$ 55.2	$ 51.6	$ 112.2	$ 95.4

Investments in Unconsolidated_5

Investments in Unconsolidated Affiliates (Schedule of Equity (Earnings) Losses from Unconsolidated Affiliates) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Schedule of Equity Method Investments [Line Items]
Equity earnings from unconsolidated affiliates	$ (26.3)	$ (24.9)	$ (53.5)	$ (45.7)
WAVE [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from unconsolidated affiliates	(26.5)	(24.9)	(53.9)	(45.7)
Overcast [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from unconsolidated affiliates	$ 0.2	$ 0	$ 0.4	$ 0

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill, Estimated Useful Life	Indefinite
Amortizing intangible assets, Gross Carrying Amount	$ 355.6	$ 315.7
Amortizing intangible assets, Accumulated Amortization	257.5	248.5
Non-amortizing intangible assets	345.3	345.2
Total intangible assets	700.9	660.9
Goodwill	$ 193.8	175.5
Trademarks And Brand Names [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Non-amortizing intangible assets, Estimated Useful Life	Indefinite
Customer Relationships [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Gross Carrying Amount	$ 200.1	183.6
Amortizing intangible assets, Accumulated Amortization	$ 157.9	152.1
Customer Relationships [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	2 years
Customer Relationships [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	20 years
Developed Technology [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Gross Carrying Amount	$ 103.1	101.4
Amortizing intangible assets, Accumulated Amortization	$ 85	84.4
Developed Technology [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	13 years
Developed Technology [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	20 years
Software [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Gross Carrying Amount	$ 17.5	15.6
Amortizing intangible assets, Accumulated Amortization	$ 6	4.6
Software [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	5 years
Software [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	7 years
Trademarks And Brand Names [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Gross Carrying Amount	$ 21.2	6.2
Amortizing intangible assets, Accumulated Amortization	$ 3.8	3.4
Trademarks And Brand Names [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	3 years
Trademarks And Brand Names [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	20 years
Non-compete Agreements [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Gross Carrying Amount	$ 9.7	6.1
Amortizing intangible assets, Accumulated Amortization	$ 4.4	3.8
Non-compete Agreements [Member] | Minimum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	3 years
Non-compete Agreements [Member] | Maximum [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	5 years
Other [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Amortizing intangible assets, Estimated Useful Life	Various
Amortizing intangible assets, Gross Carrying Amount	$ 4	2.8
Amortizing intangible assets, Accumulated Amortization	$ 0.4	$ 0.2

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Schedule of Amortization Expense) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 9.4	$ 7.1

Other Non-Current Assets (Detai

Other Non-Current Assets (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Other Assets, Noncurrent Disclosure [Abstract]
Cash surrender value of company-owned life insurance policies	$ 37.9	$ 40.3
Investment in employee deferred compensation plans	12.4	8.3
Fair value of derivative assets	0.3	1.8
Other	1.2	0.9
Total other non-current assets	$ 51.8	$ 51.3

Accounts Payable And Accrued _3

Accounts Payable And Accrued Expenses (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Payables, trade and other	$ 106.4	$ 91
Employment costs	21.2	33.6
Current portion of pension and postretirement liabilities	8	8
Other	27.4	27.3
Total accounts payable and accrued expenses	$ 163	$ 159.9

Income Tax Expenses (Details)

Income Tax Expenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Earnings before income taxes	$ 87.1	$ 80	$ 167.3	$ 143.9
Income tax expense	$ 21.2	$ 19.8	$ 41.5	$ 36.4
Effective tax rate	24.30%	24.80%	24.80%	25.30%

Debt (Narrative) (Details)

Debt (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit availability	$ 175
Amount outstanding	7.4
Term Loan A [Member]
Debt Instrument [Line Items]
Line of credit availability	450
Principal debt outstanding	438.7	$ 450
Bi-lateral Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit availability	25
Amount outstanding	7.4
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit availability	500
Amount outstanding	208	$ 140
Revolving Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit availability	150
Senior Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility amount	$ 950

Debt (Schedule of Letters of Cr

Debt (Schedule of Letters of Credit Facilities) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	$ 175
Letters of credit, Used	7.4
Letters of credit, Available	167.6
Letter of Credit [Member] | Bi-lateral Facility [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	25
Letters of credit, Used	7.4
Letters of credit, Available	17.6
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	500
Letters of credit, Used	208	$ 140
Revolving Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit, Limit	150
Letters of credit, Available	$ 150

Pensions and Other Benefit Pr_3

Pensions and Other Benefit Programs (Schedule of Periodic Benefit Costs (Credits) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
U.S. Defined-Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost of benefits earned during the period	$ 0.6	$ 0.6	$ 1.2	$ 1.3
Interest cost on projected benefit obligation	4.2	4.3	8.4	8.5
Expected return on plan assets	(6.1)	(6.3)	(12.2)	(12.5)
Amortization of net actuarial (gain) loss	1.3	1.4	2.6	2.7
Net periodic pension/postretirement cost (credit)	0	0	0	0
Retiree Health And Life Insurance Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost on projected benefit obligation	0.5	0.7	1	1.4
Amortization of prior service credit	0	(0.1)	(0.1)	(0.1)
Amortization of net actuarial (gain) loss	(2.1)	(1.4)	(4.2)	(2.9)
Net periodic pension/postretirement cost (credit)	$ (1.6)	$ (0.8)	$ (3.3)	$ (1.6)

Financial Instruments and Con_3

Financial Instruments and Contingent Consideration (Estimated Fair Value of Financial Instruments) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, including current portion	$ (644)	$ (586.8)
Acquisition-related contingent consideration	(2)	(1.6)
Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total long-term debt, including current portion	(644)	(586.8)
Acquisition-related contingent consideration	(2)	(1.6)
Interest Rate Swap Contracts [Member] | Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	1.3	(0.4)
Interest Rate Swap Contracts [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	$ 1.3	$ (0.4)

Financial Instruments and Con_4

Financial Instruments and Contingent Consideration (Summary of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration	$ 0	$ 0
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Acquisition-related contingent consideration	(2)	(1.6)
Interest Rate Swap Contracts [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	1.3	(0.4)
Interest Rate Swap Contracts [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swap contracts	$ 0	$ 0

Financial Instruments and Con_5

Financial Instruments and Contingent Consideration (Schedule of Weighted-average Of Significant Unobservable Inputs) (Details)	Jun. 30, 2024
BOK Modern, LLC [Member] | Volatility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Volatility	23.20%
BOK Modern, LLC [Member] | Discount Rates [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Discount rates	5.10%
Insolcorp L L C [Member] | Volatility [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Volatility	21.20%
Insolcorp L L C [Member] | Discount Rates [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Discount rates	5.10%

Financial Instruments and Con_6

Financial Instruments and Contingent Consideration (Schedule of Changes in Fair Value of the Acquisition Related Contingent Consideration Liability) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2024	Jun. 30, 2023
Business Combinations [Abstract]
Fair value of contingent consideration as of beginning of period	$ 1.3	$ 1.6	$ 15.2
Cash consideration paid	0	0	(15.2)
Loss related to change in fair value of contingent consideration	0.7	0.4	0
Fair value of contingent consideration as of end of period	$ 2	$ 2	$ 0
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability

Financial Instruments and Con_7

Financial Instruments and Contingent Consideration (Additional Information) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023
Business Acquisition [Line Items]
Acquisition-related contingent consideration	$ 1.5	$ 1.6
Accounts payable and accrued expenses	163	159.9
T U R F Design Inc [Member]
Business Acquisition [Line Items]
Cash consideration paid			$ (15.2)
Insolcorp and BOK [Member]
Business Acquisition [Line Items]
Accounts payable and accrued expenses	0.5
Fair Value, Inputs, Level 3 [Member]
Business Acquisition [Line Items]
Business combination, consideration transferred estimated fair value	$ 2	$ 1.6

Derivative Financial Instrume_3

Derivative Financial Instruments (Summary of Interest Rate Swaps) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
March 2021 to March 2025 [Member]
Derivative [Line Items]
Trade Date	Nov. 28, 2018
Notional Amount	$ 100
Coverage Period	March 2021 to March 2025
Risk Coverage	USD-SOFR
November 2023 to December 2025[Member]
Derivative [Line Items]
Trade Date	Oct. 23, 2023
Notional Amount	$ 50
Coverage Period	November 2023 to December 2025
Risk Coverage	USD-SOFR
March 2024 to June 2026[Member]
Derivative [Line Items]
Trade Date	Mar. 25, 2024
Notional Amount	$ 50
Coverage Period	March 2024 to June 2026
Risk Coverage	USD-SOFR
November 2023 to December 2026[Member]
Derivative [Line Items]
Trade Date	Oct. 10, 2023
Notional Amount	$ 50
Coverage Period	November 2023 to December 2026
Risk Coverage	USD-SOFR
March 2024 to June 2027[Member]
Derivative [Line Items]
Trade Date	Mar. 27, 2024
Notional Amount	$ 50
Coverage Period	March 2024 to June 2027
Risk Coverage	USD-SOFR
November 2023 to November 2027[Member]
Derivative [Line Items]
Trade Date	Sep. 29, 2023
Notional Amount	$ 50
Coverage Period	November 2023 to November 2027
Risk Coverage	USD-SOFR
June 2024 to June 2028 [Member]
Derivative [Line Items]
Trade Date	Jun. 26, 2024
Notional Amount	$ 50
Coverage Period	June 2024 to June 2028
Risk Coverage	USD-SOFR

Derivative Financial Instrume_4

Derivative Financial Instruments (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2024 USD ($)
Derivative [Line Items]
Gain in AOCI expected to be recognized in earnings over the next twelve months	$ 3.4
Interest Rate Swap Contracts [Member]
Derivative [Line Items]
SOFR floor	0%

Derivative Financial Instrume_5

Derivative Financial Instruments (Summary of Fair Value of Derivative Instruments on Consolidated Balance Sheet) (Details) - Interest Rate Swap Contracts [Member] - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Other Current Assets [Member]
Derivatives Fair Value [Line Items]
Derivative Assets, Fair Value	$ 1.5	$ 1.1
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Other Non-Current Assets [Member]
Derivatives Fair Value [Line Items]
Derivative Assets, Fair Value	$ 0.3	$ 1.8
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Accounts Payable and Accrued Expenses [Member]
Derivatives Fair Value [Line Items]
Derivative Liabilities, Fair Value	$ 0	$ 0.1
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Accrued Liabilities, Current	Accounts Payable and Accrued Liabilities, Current
Other Long-Term Liabilities [Member]
Derivatives Fair Value [Line Items]
Derivative Liabilities, Fair Value	$ 0.5	$ 3.2
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent

Derivative Financial Instrume_6

Derivative Financial Instruments (Summary of Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Derivative Instruments Gain Loss [Line Items]
Derivative Instrument, Gain (Loss) Reclassified from AOCI into Income, Effective Portion, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Comprehensive Income (Loss), Net of Tax	Other Comprehensive Income (Loss), Net of Tax	Other Comprehensive Income (Loss), Net of Tax	Other Comprehensive Income (Loss), Net of Tax
Derivatives in Cash Flow Hedging Relationships [Member] | Interest Rate Swap Contracts [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain Recognized in AOCI			$ 4.3	$ 2.1
Gain reclassified from AOCI into net earnings	$ 1.2	$ 2.9	$ 3.3	$ 5.3

Other Long-Term Liabilities (Sc

Other Long-Term Liabilities (Schedule of Other Long-Term Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Acquisition-related contingent consideration	$ 1.5	$ 1.6
Total other long-term liabilities	$ 26.2	$ 26.8

Shareholders' Equity (Narrative

Shareholders' Equity (Narrative) (Details) - USD ($)				1 Months Ended		3 Months Ended		6 Months Ended
	Aug. 08, 2024	Jul. 24, 2024	Jul. 29, 2016	Apr. 30, 2024	Feb. 29, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	May 31, 2024	Mar. 31, 2024
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, repurchased cost						$ 10,100,000	$ 30,300,000	$ 25,300,000	$ 57,600,000
Quarterly dividends declared				$ 0.28	$ 0.28
Dividends declared						$ 0.28	$ 0.254	$ 0.56	$ 0.508
Dividends payable, date to be paid, year and month										2024-05	2024-03
Subsequent Event [Member]
Equity Class Of Treasury Stock [Line Items]
Quarterly dividends declared		$ 0.28
Scenario Forecast [Member]
Equity Class Of Treasury Stock [Line Items]
Dividend payable, date to be paid day month and year	Aug. 22, 2024
Common Stock
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, expiration date			Dec. 31, 2026
Stock repurchase program, remaining authorized repurchase amount						$ 691,800,000		$ 691,800,000
Shares repurchase program, shares repurchased						(83,811)	(443,376)	(226,393)	(810,645)
Common Stock | Share Repurchase Program Excluding Accelerated Share Repurchase
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, shares repurchased						100,000		200,000
Shares repurchase program, repurchased cost						$ 10,000,000		$ 25,000,000
Shares repurchase program, average price per share						$ 119.32		$ 110.43
Common Stock | Share Repurchase Program Including Accelerated Share Repurchase
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, shares repurchased								14,400,000
Shares repurchase program, repurchased cost								$ 1,008,200,000
Shares repurchase program, average price per share								$ 69.97
Common Stock | July 2018 Program [Member] | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount			$ 150,000,000
Common Stock | December 2026 Program [Member] | Maximum [Member]
Equity Class Of Treasury Stock [Line Items]
Shares repurchase program, authorized amount			$ 1,700,000,000

Shareholders' Equity (Schedule

Shareholders' Equity (Schedule of Accumulated Other Comprehensive (Loss) Activity) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 626.8	$ 544.8	$ 591.8	$ 535
Ending Balance		669	566.7	669	566.7
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	0.2	0.4	1	0.5
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	[1]	(0.4)	0.7	(1.2)	0.6
Amounts reclassified from accumulated other comprehensive (loss)	[1]	0	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	[1]	(0.4)	0.7	(1.2)	0.6
Ending Balance	[1]	(0.2)	1.1	(0.2)	1.1
Derivative (Loss) Gain [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	1	7.3	0.5	9.5
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	[1]	1.1	2.1	3.3	1.8
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(0.9)	(2.3)	(2.6)	(4.2)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	[1]	0.2	(0.2)	0.7	(2.4)
Ending Balance	[1]	1.2	7.1	1.2	7.1
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(106.8)	(109.9)	(106.2)	(110.1)
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	[1]	0	(0.1)	0	0.3
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(0.7)	0	(1.3)	(0.2)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	[1]	(0.7)	(0.1)	(1.3)	0.1
Ending Balance	[1]	(107.5)	(110)	(107.5)	(110)
Accumulated Other Comprehensive (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	[1]	(105.6)	(102.2)	(104.7)	(100.1)
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	[1]	0.7	2.7	2.1	2.7
Amounts reclassified from accumulated other comprehensive (loss)	[1]	(1.6)	(2.3)	(3.9)	(4.4)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent, Total	[1]	(0.9)	0.4	(1.8)	(1.7)
Ending Balance	[1]	$ (106.5)	$ (101.8)	$ (106.5)	$ (101.8)
[1] (1) Amounts are net of tax.

Shareholders' Equity (Schedul_2

Shareholders' Equity (Schedule of Accumulated Other Comprehensive (Loss) Activity) (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	$ 0	$ 0	$ 0.1	$ 0
Derivative (Loss) Gain [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	(0.3)	(0.5)	(1)	(0.3)
Pension And Postretirement Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	0	0.1	0	(0.1)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive (loss) income before reclassifications, net of tax benefit (expense)	$ (0.3)	$ (0.4)	$ (0.9)	$ (0.4)

Shareholders' Equity (Reclassif

Shareholders' Equity (Reclassification out of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	$ (11.1)	$ (9.2)	$ (20.1)	$ (17.9)
Tax impact	(21.2)	(19.8)	(41.5)	(36.4)
Total (income), net of tax	(65.9)	(60.2)	(125.8)	(107.5)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Derivative (Loss) Gain [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax impact	0.1	0.1	0.4	0.1
Total (income), net of tax	(0.9)	(2.3)	(2.6)	(4.2)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Derivative (Loss) Gain [Member] | Interest Rate Swap Contracts, Before Tax [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(1.2)	(2.9)	(3.3)	(5.3)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Prior Service Credit Amortization [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other non-operating (income), net	0	(0.1)	(0.1)	(0.1)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Amortization of Net Actuarial Loss [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other non-operating (income), net	(0.8)	0	(1.6)	(0.2)
Reclassification From Accumulated Other Comprehensive Loss [Member] | Pension And Postretirement Adjustments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax impact	0.3	0.6	0.7	1.1
Total loss, before tax	(0.8)	(0.1)	(1.7)	(0.3)
Total loss, net of tax	(0.7)	0	(1.3)	(0.2)
Total reclassifications for the period	$ (1.6)	$ (2.3)	$ (3.9)	$ (4.4)

Litigation and Related Matters

Litigation and Related Matters (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended	48 Months Ended
	Sep. 30, 2010 Site	Jun. 30, 2024 USD ($)	Jun. 30, 2024 USD ($) Site	Dec. 31, 2007	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)
Loss Contingencies [Line Items]
Settlement agreement amount of litigation agreement					$ 53
Environmental insurance recoveries received in excess of cumulative expenses incurred						$ 2.6
Estimated cost for non-groundwater elements			$ 8
Reserves for potential environmental liabilities		$ 4	$ 4
Macon Site [Member]
Loss Contingencies [Line Items]
Number of landfills listed as Superfund site | Site			2
Number of landfills AWI entered into an Administrative Order on Consent for a Removal Action | Site	1
Submission date of final report to EPA	Oct. 31, 2016
Elizabeth City [Member]
Loss Contingencies [Line Items]
Percentage of site costs Navy agreed to pay				33.33%
Cost of goods sold [Member]
Loss Contingencies [Line Items]
Reserves for potential environmental liabilities		2.5	$ 2.5
SG&A Expenses [Member]
Loss Contingencies [Line Items]
Reserves for potential environmental liabilities		1.5	1.5
Other Long-Term Liabilities [Member]
Loss Contingencies [Line Items]
Environmental liabilities		$ 4.2	$ 4.2			$ 0.5

Net Earnings Per Share (Reconci

Net Earnings Per Share (Reconciliation of Net Earnings Attributable to Common Shares Used in Basic and Diluted Net Earnings Per Share Calculation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net earnings	$ 65.9	$ 60.2	$ 125.8	$ 107.5
(Earnings) allocated to participating vested share awards	0	0	0	(0.1)
(Earnings) allocated to participating vested share awards	0	0	0	(0.1)
Net earnings attributable to common shares	$ 65.9	$ 60.2	$ 125.8	$ 107.4

Net Earnings Per Share (Recon_2

Net Earnings Per Share (Reconciliation of Basic Shares Outstanding to Diluted Shares Outstanding) (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Basic shares outstanding	43.8	44.9	43.8	45.2
Dilutive effect of common stock equivalents	0.2	0.1	0.2	0
Diluted shares outstanding	44	45	44	45.2

Net Earnings Per Share (Narrati

Net Earnings Per Share (Narrative) (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Common stock equivalents not included in the computation of diluted EPS	0	191,659	17,426	133,144