Mueller Industries (MLI) 10-Q 20 Oct 21 2021 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 25, 2021	Oct. 15, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 25, 2021
Document Transition Report	false
Entity File Number	1-6770
Entity Registrant Name	MUELLER INDUSTRIES INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	25-0790410
Entity Address, Address Line One	150 Schilling Boulevard
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Collierville
Entity Address, State or Province	TN
Entity Address, Postal Zip Code	38017
City Area Code	901
Local Phone Number	753-3200
Title of 12(b) Security	Common Stock
Trading Symbol	MLI
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		57,366,709
Entity Central Index Key	0000089439
Current Fiscal Year End Date	--12-25
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Income Statement [Abstract]
Net sales	$ 982,248	$ 619,105	$ 2,812,988	$ 1,722,192
Cost of goods sold	744,265	500,780	2,212,395	1,412,654
Depreciation and amortization	10,868	10,752	33,757	32,888
Selling, general, and administrative expense	48,524	38,346	137,891	117,749
Gain on sale of businesses	(54,759)	0	(54,759)	0
Litigation settlement, net	0	0	0	(21,933)
Operating income	233,350	69,227	483,704	180,834
Interest expense	(1,116)	(4,885)	(7,451)	(15,237)
Redemption premium	0	0	(5,674)	0
Other (expense) income, net	(2,548)	522	(1,288)	3,634
Income before income taxes	229,686	64,864	469,291	169,231
Income tax expense	(60,229)	(15,450)	(120,996)	(42,623)
Income (loss) from unconsolidated affiliates, net of foreign tax	2,799	(5,457)	131	(20,213)
Consolidated net income	172,256	43,957	348,426	106,395
Net income attributable to noncontrolling interests	(1,276)	(1,255)	(5,507)	(3,322)
Net income attributable to Mueller Industries, Inc.	$ 170,980	$ 42,702	$ 342,919	$ 103,073
Weighted average shares for basic earnings per share (in shares)	56,077	55,816	55,979	55,805
Effect of dilutive stock-based awards (in shares)	731	550	784	534
Adjusted weighted average shares for diluted earnings per share (in shares)	56,808	56,366	56,763	56,339
Basic earnings per share (in dollars per share)	$ 3.05	$ 0.77	$ 6.13	$ 1.85
Diluted earnings per share (in dollars per share)	3.01	0.76	6.04	1.83
Dividends per share (in dollars per share)	$ 0.13	$ 0.10	$ 0.39	$ 0.30

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 172,256	$ 43,957	$ 348,426	$ 106,395
Other comprehensive (loss) income, net of tax:
Foreign currency translation	(8,569)	9,320	(667)	(11,514)
Net change with respect to derivative instruments and hedging activities, net of tax of $(610), $(43), $204, and $(53)	2,122	151	(722)	192
Net change in pension and postretirement obligation adjustments, net of tax of $(137), $92, $(80), and $224	493	(170)	476	(715)
Attributable to unconsolidated affiliates, net of tax of $(284), $(99), $(642), and $163	977	339	2,211	(564)
Total other comprehensive (loss) income, net	(4,977)	9,640	1,298	(12,601)
Consolidated comprehensive income	167,279	53,597	349,724	93,794
Comprehensive income attributable to noncontrolling interests	(192)	(2,207)	(4,077)	(3,062)
Comprehensive income attributable to Mueller Industries, Inc.	$ 167,087	$ 51,390	$ 345,647	$ 90,732

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Statement of Comprehensive Income [Abstract]
Net change with respect to derivative instruments and hedging activities, tax (expense) benefit	$ (610)	$ (43)	$ 204	$ (53)
Net actuarial loss on pension and postretirement obligations, tax benefit (expense)	(137)	92	(80)	224
Attributable to unconsolidated affiliates, tax benefit (expense)	$ (284)	$ (99)	$ (642)	$ 163

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 25, 2021	Dec. 26, 2020
Current assets:
Cash and cash equivalents	$ 104,789	$ 119,075
Accounts receivable, less allowance for doubtful accounts of $2,687 in 2021 and $1,538 in 2020	493,960	357,532
Inventories	405,590	315,002
Other current assets	33,604	33,752
Total current assets	1,037,943	825,361
Property, plant, and equipment, net	370,222	376,572
Operating lease right-of-use assets	24,147	29,301
Goodwill, net	159,988	167,764
Intangible assets, net	63,579	77,207
Investments in unconsolidated affiliates	65,000	37,976
Other assets	7,658	14,387
Total assets	1,728,537	1,528,568
Current liabilities:
Current portion of debt	1,110	41,283
Accounts payable	180,509	147,741
Accrued wages and other employee costs	49,932	46,299
Current portion of operating lease liabilities	6,193	6,259
Other current liabilities	142,354	98,061
Total current liabilities	380,098	339,643
Long-term debt, less current portion	121,012	286,593
Pension liabilities	10,901	13,552
Postretirement benefits other than pensions	13,231	13,289
Environmental reserves	20,902	21,256
Deferred income taxes	13,393	16,842
Noncurrent operating lease liabilities	17,399	21,602
Other noncurrent liabilities	25,369	14,731
Total liabilities	602,305	727,508
Mueller Industries, Inc. stockholders' equity:
Preferred stock - $1.00 par value; shares authorized 5,000,000; none outstanding	0	0
Common stock - $.01 par value; shares authorized 100,000,000; issued 80,183,004; outstanding 57,367,709 in 2021 and 57,087,432 in 2020	802	802
Additional paid-in capital	283,285	280,051
Retained earnings	1,340,337	1,019,694
Accumulated other comprehensive loss	(52,155)	(54,883)
Treasury common stock, at cost	(464,707)	(468,919)
Total Mueller Industries, Inc. stockholders' equity	1,107,562	776,745
Noncontrolling interests	18,670	24,315
Total equity	1,126,232	801,060
Commitments and contingencies	0	0
Total liabilities and equity	$ 1,728,537	$ 1,528,568

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 25, 2021	Dec. 26, 2020
Current assets:
Allowance for doubtful accounts	$ 2,687	$ 1,538
Mueller Industries, Inc. stockholders' equity:
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	80,183,004	80,183,004
Common stock, shares outstanding (in shares)	57,367,709	57,087,432

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020
Cash flows from operating activities
Consolidated net income	$ 348,426	$ 106,395
Reconciliation of consolidated net income to net cash provided by operating activities:
Depreciation and amortization	33,932	33,127
Stock-based compensation expense	7,228	6,332
Provision for doubtful accounts receivable	1,310	953
(Income) loss from unconsolidated affiliates	(131)	20,213
Redemption premium	5,674	0
(Gain) loss on disposals of properties	(1,135)	144
Gain on sale of businesses	(54,759)	0
Impairment charges	2,568	3,035
Deferred income tax expense (benefit)	6,304	(836)
Changes in assets and liabilities, net of effects of businesses acquired and sold:
Receivables	(155,103)	(45,530)
Inventories	(96,505)	41,598
Other assets	(9,335)	9,053
Current liabilities	85,523	25,913
Other liabilities	8,335	(5,813)
Other, net	(851)	2,294
Net cash provided by operating activities	181,481	196,878
Cash flows from investing activities
Capital expenditures	(25,547)	(29,204)
Acquisition of businesses, net of cash acquired	(13,935)	(72,648)
Proceeds from sale of businesses, net of cash sold	74,250	0
Investments in unconsolidated affiliates	(1,613)	0
Payment received for (issuance of) notes receivable	8,539
Payment received for (issuance of) notes receivable		(9,155)
Proceeds from sales of assets	2,124	12
Net cash provided by (used in) investing activities	43,818	(110,995)
Cash flows from financing activities
Dividends paid to stockholders of Mueller Industries, Inc.	(21,846)	(16,754)
Dividends paid to noncontrolling interests	(9,722)	0
Repurchase of common stock	0	(5,574)
Payment of contingent consideration	(1,250)	(7,000)
Issuance of debt	475,000	150,027
Repayments of debt	(680,572)	(186,492)
Repayment of debt by consolidated joint ventures, net	(4,865)	(299)
Net cash received (used) to settle stock-based awards	219
Net cash received (used) to settle stock-based awards		(160)
Debt issuance costs	(1,111)	0
Net cash used in financing activities	(244,147)	(66,252)
Effect of exchange rate changes on cash	(377)	(3,294)
(Decrease) increase in cash, cash equivalents, and restricted cash	(19,225)	16,337
Cash, cash equivalents, and restricted cash at the beginning of the period	127,376	98,042
Cash, cash equivalents, and restricted cash at the end of the period	$ 108,151	$ 114,379

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated other comprehensive loss	Treasury Stock	Noncontrolling Interest
Balance at beginning of period at Dec. 28, 2019		$ 802	$ 278,609	$ 903,070	$ (68,770)	$ (470,243)	$ 18,668
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition (issuance) of shares under incentive stock option plans			(896)			719
Stock-based compensation expense			6,332
Issuance of restricted stock			(6,382)			6,382
Net income attributable to Mueller Industries, Inc.	$ 103,073			103,073
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(17,160)
Total other comprehensive (loss) income attributable to Mueller Industries, Inc.	(12,601)				(12,341)
Repurchase of common stock						(5,574)
Dividends paid to noncontrolling interests							0
Net income attributable to noncontrolling interests	(3,322)						3,322
Foreign currency translation	(11,514)						(260)
Balance at end of period at Sep. 26, 2020		802	277,663	988,983	(81,111)	(468,716)	21,730
Balance at beginning of period at Jun. 27, 2020		802	281,856	951,992	(89,799)	(474,170)	19,523
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition (issuance) of shares under incentive stock option plans			(229)			(644)
Stock-based compensation expense			2,134
Issuance of restricted stock			(6,098)			6,098
Net income attributable to Mueller Industries, Inc.	42,702			42,702
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(5,711)
Total other comprehensive (loss) income attributable to Mueller Industries, Inc.	9,640				8,688
Repurchase of common stock						0
Dividends paid to noncontrolling interests							0
Net income attributable to noncontrolling interests	(1,255)						1,255
Foreign currency translation	9,320						952
Balance at end of period at Sep. 26, 2020		802	277,663	988,983	(81,111)	(468,716)	21,730
Balance at beginning of period at Dec. 26, 2020	801,060	802	280,051	1,019,694	(54,883)	(468,919)	24,315
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition (issuance) of shares under incentive stock option plans			728			(484)
Stock-based compensation expense			7,228
Issuance of restricted stock			(4,722)			4,722
Net income attributable to Mueller Industries, Inc.	342,919			342,919
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(22,276)
Total other comprehensive (loss) income attributable to Mueller Industries, Inc.	1,298				2,728
Repurchase of common stock						(26)
Dividends paid to noncontrolling interests							(9,722)
Net income attributable to noncontrolling interests	(5,507)						5,507
Foreign currency translation	(667)						(1,430)
Balance at end of period at Sep. 25, 2021	1,126,232	802	283,285	1,340,337	(52,155)	(464,707)	18,670
Balance at beginning of period at Jun. 26, 2021		802	285,148	1,176,812	(48,262)	(468,784)	28,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition (issuance) of shares under incentive stock option plans			163			(360)
Stock-based compensation expense			2,411
Issuance of restricted stock			(4,437)			4,437
Net income attributable to Mueller Industries, Inc.	170,980			170,980
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(7,455)
Total other comprehensive (loss) income attributable to Mueller Industries, Inc.	(4,977)				(3,893)
Repurchase of common stock						0
Dividends paid to noncontrolling interests							(9,722)
Net income attributable to noncontrolling interests	(1,276)						1,276
Foreign currency translation	(8,569)						(1,084)
Balance at end of period at Sep. 25, 2021	$ 1,126,232	$ 802	$ 283,285	$ 1,340,337	$ (52,155)	$ (464,707)	$ 18,670

Recent Accounting Standards

Recent Accounting Standards	9 Months Ended
	Sep. 25, 2021
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Standards	Recent Accounting Standards Adopted In October 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2020-10, Codification Improvements: An Amendment of the FASB Accounting Standards Codification . The ASU facilitates updates to the Accounting Standards Codification for technical corrections such as conforming amendments, clarifications to guidance, simplifications to wording or structure of guidance, and other minor improvements. The Company adopted the ASU during the first quarter of 2021 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 . The new guidance addresses accounting for the transition into and out of the equity method and measuring certain purchased options and forward contracts to acquire investments. The Company adopted the ASU during the first quarter of 2021 using a prospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes . The new guidance affects general principles within Topic 740, Income Taxes. The amendments of ASU 2019-12 are meant to simplify and reduce the cost of accounting for income taxes. The Company adopted the ASU during the first quarter of 2021 using a prospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. Issued In January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): An Amendment of the FASB Accounting Standards Codification. The new guidance was issued in response to concerns about structural risks of interbank offered rates, and, particularly, the risk of cessation of the London Interbank Offered Rate (LIBOR). Regulators in numerous jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction based and less susceptible to manipulation. The ASU is effective in 2021 but can be applied through December 31, 2022. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements.

Earnings per Common Share

Earnings per Common Share	9 Months Ended
	Sep. 25, 2021
Earnings Per Share [Abstract]
Earnings per Common Share	Earnings per Common Share Basic per share amounts have been computed based on the average number of common shares outstanding. Diluted per share amounts reflect the increase in average common shares outstanding that would re sult from the assumed exercise of outstanding stock options and vesting of restricted stock awards, computed using the treasury stock method. Approximately 30 thousand and three thousand stock-based awards were excluded from the computation of diluted earnings per share for the quarters ended September 25, 2021 and September 26, 2020, respectively, because they were antidilutive.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 25, 2021
Business Combination and Asset Acquisition [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Acquisitions H&C Flex On December 20, 2020, the Company entered into an asset purchase agreement with Hart & Cooley LLC. The transaction closed on January 29, 2021, whereby the Company purchased the Hart & Cooley flexible duct business, which included inventory, manufacturing equipment, and related assets for approximately $15.3 million . The total purchase price consisted of $14.0 million in cash paid at closing and a contingent consideration arrangement of $1.3 million. The Company treated this as a business combination. The acquired business, H&C Flex, is a manufacturer and distributor of insulated HVAC flexible duct systems. It is reported within and complements the Company’s existing businesses in the Climate segment. As of September 25, 2021, the provisional fair value of tangible assets acquired totaled $15.3 million, consisting primarily of property, plant, and equipment of $10.8 million and inventory of $4.5 million. Of the remaining purchase price, $0.1 million was allocated to tax-deductible goodwill. During the second quarter of 2021, there was a change in the valuation that resulted in an increase in property, plant, and equipment of $2.4 million, a decrease in goodwill of $1.0 million, and the recognition of contingent consideration of $1.4 million. The purchase price allocation is provisional as of September 25, 2021 and subject to change upon completion of the final valuation of the assets and contingent consideration during the measurement period. Kessler Sales and Distribution, LLC On August 3, 2020, the Company entered into an asset purchase agreement with Wieland-Kessler LLC, whereby the Company purchased the Kessler distribution business, which included inventory, manufacturing equipment, and related assets. The total purchase price was $57.2 million in cash paid at closing. The Company treated this as a business combination. The acquired business, Kessler Sales and Distribution, LLC, is a distributor of residential and commercial plumbing products. It is reported within and complements the Company’s existing businesses in the Piping Systems segment. The fair value of tangible assets acquired totaled $27.3 million, consisting primarily of inventory. Of the remaining purchase price, $29.9 million was allocated to tax-deductible goodwill and intangible assets. During the second quarter of 2021, there was a change in the valuation that resulted in a decrease in property, plant, and equipment and an increase in goodwill of $1.4 million. During the first quarter of 2021, there was a change in the valuation that resulted in a decrease in goodwill and an increase in intangible assets of $1.5 million. The valuation of the business has been finalized as of September 25, 2021. Shoals Tubular, Inc. On January 17, 2020, the Company entered into a stock purchase agreement pursuant to which the Company acquired all of the outstanding stock of Shoals Tubular, Inc. (STI) for approximately $15.3 million, net of working capital adjustments. The total purchase price consisted of $15.3 million in cash at closing. STI is a manufacturer of brazed manifolds, headers, and distributor assemblies used primarily by manufacturers of residential heating and air conditioning units. The acquired business is reported within and complements the Company’s existing businesses in the Climate segment. The fair value of the tangible assets acquired totaled $6.2 million, consisting primarily of property, plant, and equipment of $3.7 million, inventories of $1.8 million, and accounts receivable of $0.7 million. The fair value of the liabilities assumed totaled $0.2 million, consisting primarily of accounts payable. Of the remaining purchase price, $9.3 million was allocated to tax-deductible goodwill and intangible assets. The valuation of the business has been finalized. There were no material changes to the purchase price allocation from the amounts presented in the Company’s 2020 Annual Report on Form 10-K. Dispositions Die-Mold On September 2, 2021, the Company entered into a contribution agreement with a limited liability company in the retail distribution business, pursuant to which the Company exchanged the outstanding common stock of Die-Mold for a 17 percent equity interest in the limited liability company. Die-Mold manufactures PEX and other plumbing-related fittings and plastic injection tooling in Canada and sells these products in Canada and the U.S. and was included in the Piping Systems Segment. Die-Mold reported net sales of $10.9 million and net income of $1.6 million for the first nine months of 2021 compared to net sales of $10.4 million and net income of $1.4 million in the first nine months of 2020. As a result of the transaction, the Company recognized a gain of $4.7 million based on the excess of the fair value of the consideration received (the 17 percent equity interest) over the carrying value of Die-Mold. The Company utilized a market comparable companies approach using an EBITDA multiple to determine the fair value of the consideration received of $24.0 million, which is recognized within the Investments in unconsolidated affiliates line of the Condensed Consolidated Balance Sheet. The excess of the fair value of the deconsolidated subsidiary over its carrying value resulted in the gain. Fabricated Tube Products and Shoals Tubular, Inc. On July 28, 2021, the Company entered into a purchase agreement with J.W. Harris Co., Inc. and Lincoln Electric Holdings, Inc., pursuant to which the Company sold the assets of Fabricated Tube Products (FTP) and all of the outstanding stock of STI for approximately $78.2 million. These businesses manufacture and fabricate valves and assemblies, brazed manifolds, headers, and distributor assemblies used primarily by manufacturers of residential heating and air conditioning units in the U.S. and were included in the Climate segment. They reported combined net sales of $37.0 million and net income of $5.5 million in the first nine months of 2021 compared to combined net sales of $38.3 million and net income of $4.8 million in the first nine months of 2020. The carrying value of the assets disposed totaled $31.7 million, consisting primarily of accounts receivable, inventories, and long-lived assets. The carrying value of the liabilities disposed totaled $3.6 million, consisting primarily of accounts payable. As a result of the transaction, the Company recognized a pre-tax gain of $50.1 million on the sale of these businesses in the Condensed Consolidating Financial Statements.

Segment Information

Segment Information	9 Months Ended
	Sep. 25, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information Each of the Company’s reportable segments is composed of certain operating segments that are aggregated primarily by the nature of products offered as follows: Piping Systems Piping Systems is composed of the following operating segments: Domestic Piping Systems Group, Great Lakes Copper, Heatlink Group, European Operations, Trading Group, an d Jungwoo-Mueller (the Company’s South Korean joint venture). The Domestic Piping Systems Group manufactures and distributes copper tube, fittings, and line sets. These products are manufactured in the U.S., sold in the U.S., and exported to markets worldwide. Outside the U.S., Great Lakes Copper manufactures copper tube and line sets in Canada and sells the products primarily in the U.S. and Canada. Heatlink Group produces a complete line of products for PEX plumbing and radiant systems in Canada and sells these products in Canada and the U.S. European Operations manufactures copper tube in the U.K. which is sold primarily in Europe. The Trading Group manufactures pipe nipples and resells brass and plastic plumbing valves, malleable iron fittings, faucets, and plumbing specialty products in the U.S. and Mexico. Jungwoo-Mueller manufactures copper-based joining products that are sold worldwide. The Piping Systems segment’s products are sold primarily to plumbing, refrigeration, and air-conditioning wholesalers, hardware wholesalers and co-ops, building product retailers, and air-conditioning original equipment manufacturers (OEMs). Industrial Metals Industrial Metals is composed of the following operating segments: Brass Rod & Copper Bar Products, Impacts & Micro Gauge, and Brass Value-Added Products. These businesses manufacture brass rod, impact extrusions, and forgings, as well as a wide variety of end products including plumbing brass, automotive components, valves, fittings, and gas assemblies. These products are manufactured in the U.S. and sold primarily to OEMs in the U.S., many of which are in the industrial, transportation, construction, heating, ventilation, and air-conditioning, plumbing, refrigeration, and energy markets. Climate Climate is composed of the following operating segments: Refrigeration Products, Westermeyer, Turbotec, Flex Duct , and Linesets, Inc. These domestic businesses manufacture high pressure components, coaxial heat exchangers, insulated HVAC flexible duct systems, and line sets primarily for the heating, ventilation, air-conditioning, and refrigeration markets in the U.S. Summarized segment information is as follows: For the Quarter Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 688,200 $ 182,245 $ 122,252 $ (10,449) $ 982,248 Cost of goods sold 506,703 158,822 89,175 (10,435) 744,265 Depreciation and amortization 5,547 1,661 2,484 1,176 10,868 Selling, general, and administrative expense 23,751 2,710 9,521 12,542 48,524 Gain on sale of businesses — — — (54,759) (54,759) Operating income 152,199 19,052 21,072 41,027 233,350 Interest expense (1,116) Other (expense) income, net (2,548) Income before income taxes $ 229,686 For the Quarter Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 409,414 $ 118,831 $ 97,604 $ (6,744) $ 619,105 Cost of goods sold 339,904 95,717 70,450 (5,291) 500,780 Depreciation and amortization 5,362 1,774 2,547 1,069 10,752 Selling, general, and administrative expense 19,285 2,992 6,451 9,618 38,346 Operating income 44,863 18,348 18,156 (12,140) 69,227 Interest expense (4,885) Other income, net 522 Income before income taxes $ 64,864 Segment information (continued): For the Nine Months Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,947,564 $ 527,137 $ 364,986 $ (26,699) $ 2,812,988 Cost of goods sold 1,515,335 455,112 269,560 (27,612) 2,212,395 Depreciation and amortization 17,272 5,098 7,866 3,521 33,757 Selling, general, and administrative expense 71,152 8,529 23,781 34,429 137,891 Gain on sale of businesses — — — (54,759) (54,759) Operating income 343,805 58,398 63,779 17,722 483,704 Interest expense (7,451) Redemption premium (5,674) Other income, net (1,288) Income before income taxes $ 469,291 For the Nine Months Ended September 26, 2020 ( In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,128,467 $ 338,652 $ 276,983 $ (21,910) $ 1,722,192 Cost of goods sold 931,339 285,788 206,083 (10,556) 1,412,654 Depreciation and amortization 16,517 5,771 7,770 2,830 32,888 Selling, general, and administrative expense 57,998 8,690 19,607 31,454 117,749 Litigation settlement, net — — — (21,933) (21,933) Operating income 122,613 38,403 43,523 (23,705) 180,834 Interest expense (15,237) Other income, net 3,634 Income before income taxes $ 169,231 The following table presents total assets attributable to each segment: (In thousands) September 25, 2021 December 26, 2020 Segment assets: Piping Systems $ 1,142,523 $ 977,937 Industrial Metals 186,040 152,683 Climate 244,603 258,668 General Corporate 155,371 139,280 $ 1,728,537 $ 1,528,568 The following tables represent a disaggregation of revenue from contracts with customers, along with the reportable segment for each category: For the Quarter Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 555,161 $ — $ — $ 555,161 Brass rod and forgings — 143,788 — 143,788 OEM components, tube & assemblies 6,943 12,076 29,627 48,646 Valves and plumbing specialties 126,096 — — 126,096 Flex duct and other HVAC components — — 92,625 92,625 Other — 26,381 — 26,381 688,200 182,245 122,252 992,697 Intersegment sales (10,449) Net sales $ 982,248 For the Quarter Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 320,619 $ — $ — $ 320,619 Brass rod and forgings — 89,487 — 89,487 OEM components, tube & assemblies 7,402 11,215 35,957 54,574 Valves and plumbing specialties 81,393 — — 81,393 Flex duct and other HVAC components — — 61,647 61,647 Other — 18,129 — 18,129 409,414 118,831 97,604 625,849 Intersegment sales (6,744) Net sales $ 619,105 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,548,392 $ — $ — $ 1,548,392 Brass rod and forgings — 418,024 — 418,024 OEM components, tube & assemblies 23,954 35,819 111,143 170,916 Valves and plumbing specialties 375,218 — — 375,218 Flex duct and other HVAC components — — 253,843 253,843 Other — 73,294 — 73,294 1,947,564 527,137 364,986 2,839,687 Intersegment sales (26,699) Net sales $ 2,812,988 For the Nine Months Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings 878,764 — — 878,764 Brass rod and forgings — 253,647 — 253,647 OEM components, tube & assemblies 49,509 32,524 105,461 187,494 Valves and plumbing specialties 200,194 — — 200,194 Flex duct and other HVAC components — — 171,522 171,522 Other — 52,481 — 52,481 1,128,467 338,652 276,983 1,744,102 Intersegment sales (21,910) Net sales $ 1,722,192

Cash, Cash Equivalents, and Res

Cash, Cash Equivalents, and Restricted Cash	9 Months Ended
	Sep. 25, 2021
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash (In thousands) September 25, December 26, Cash & cash equivalents $ 104,789 $ 119,075 Restricted cash included within other current assets 3,259 8,198 Restricted cash included within other assets 103 103 Total cash, cash equivalents, and restricted cash $ 108,151 $ 127,376 Amounts included in restricted cash relate to required deposits in brokerage accounts that facilitate the Company’s hedging activities as well as imprest funds for the Company’s self-insured workers’ compensation program.

Inventories

Inventories	9 Months Ended
	Sep. 25, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories (In thousands) September 25, December 26, Raw materials and supplies $ 133,109 $ 85,927 Work-in-process 66,574 49,361 Finished goods 215,007 186,785 Valuation reserves (9,100) (7,071) Inventories $ 405,590 $ 315,002

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 25, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments Derivative Instruments and Hedging Activities The Company’s earnings and cash flows are subject to fluctuations due to changes in commodity prices, foreign currency exchange rates, and interest rates. The Company uses derivative instruments such as commodity futures contracts, foreign currency forward contracts, and interest rate swaps to manage these exposures. All derivatives are recognized in the Condensed Consolidated Balance Sheets at their fair value. On the date the derivative contract is entered into, it is either a) designated as a hedge of a forecasted transaction or the variability of cash flow to be paid (cash flow hedge) or b) not designated in a hedge accounting relationship, even though the derivative contract was executed to mitigate an economic exposure (economic hedge), as the Company does not enter into derivative contracts for trading purposes. Changes in the fair value of a derivative that is qualified, designated, and highly effective as a cash flow hedge are recorded in stockholders’ equity within AOCI, to the extent effective, until they are reclassified to earnings in the same period or periods during which the hedged transaction affects earnings. Changes in the fair value of undesignated derivatives executed as economic hedges are reported in current earnings. The Company documents all relationships between derivative instruments and hedged items, as well as the risk-management objective and strategy for undertaking various hedge transactions. This process includes linking all derivative instruments that are designated as fair value hedges to specific assets and liabilities in the Condensed Consolidated Balance Sheets and linking cash flow hedges to specific forecasted transactions or variability of cash flow. The Company also assesses, both at the hedge’s inception and on an ongoing basis, whether the designated derivative instruments that are used in hedging transactions are highly effective in offsetting changes in cash flows or fair values of hedged items. When a derivative instrument is determined not to be highly effective as a hedge or the underlying hedged transaction is no longer probable of occurring, hedge accounting is discontinued prospectively in accordance with the derecognition criteria for hedge accounting. Commodity Futures Contracts Copper and brass represent the largest component of the Company’s variable costs of production. The cost of these materials is subject to global market fluctuations caused by factors beyond the Company’s control. The Company occasionally enters into forward fixed-price arrangements with certain customers; the risk of these arrangements is generally managed with commodity futures contracts. These futures contracts have been designated as cash flow hedges. At September 25, 2021, the Company held open futures contracts to purchase approximately $46.9 million of copper over the next 18 months related to fixed price sales orders. The fair value of those futures contracts was a $112 thousand net gain position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy). In the next 12 months, the Company will reclassify into earnings realized gains or losses relating to cash flow hedges. At September 25, 2021, this amount was approximately $142 thousand of deferred net gains, net of tax. The Company may also enter into futures contracts to protect the value of inventory against market fluctuations. At September 25, 2021, the Company held open futures contracts to sell approximately $867 thousand of copper over the next 10 months related to copper inventory. The fair value of those futures contracts was a $16 thousand net loss position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy). The Company presents its derivative assets and liabilities in the Condensed Consolidated Balance Sheets on a net basis by counterparty. The following table summarizes the location and fair value of the derivative instruments and disaggregates the net derivative assets and liabilities into gross components on a contract-by-contract basis: Asset Derivatives Liability Derivatives Fair Value Fair Value (In thousands) Balance Sheet Location September 25, December 26, Balance Sheet Location September 25, December 26, Commodity contracts - gains Other current assets $ 671 $ 1,213 Other current liabilities $ 27 $ 68 Commodity contracts - losses Other current assets (559) (8) Other current liabilities (43) (5,863) Total derivatives (1) $ 112 $ 1,205 $ (16) $ (5,795) (1) Does not include the impact of cash collateral provided to counterparties. The following tables summarize the effects of derivative instruments on the Company’s Condensed Consolidated Statements of Income: For the Quarter Ended For the Nine Months Ended (In thousands) Location September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Undesignated derivatives: Gain (loss) on commodity contracts (nonqualifying) Cost of goods sold 7,282 843 (3,141) (3,596) The following tables summarize amounts recognized in and reclassified from AOCI during the period: For the Quarter Ended September 25, 2021 (In thousands) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss (Gain) Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 845 Cost of goods sold $ 1,265 Other 13 Other (1) Total $ 858 Total $ 1,264 Amounts recognized in and reclassified from AOCI (continued): For the Quarter Ended September 26, 2020 (In thousands) Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 337 Cost of goods sold $ (180) Other (6) Other — Total $ 331 Total $ (180) For the Nine Months Ended September 25, 2021 (In thousands) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 861 Cost of goods sold $ (1,584) Other 1 Other — Total $ 862 Total $ (1,584) For the Nine Months Ended September 26, 2020 (In thousands) (Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ (5,084) Cost of goods sold $ 5,273 Other 2 Other 1 Total $ (5,082) Total $ 5,274 The Company primarily enters into International Swaps and Derivatives Association master netting agreements with major financial institutions that permit the net settlement of amounts owed under their respective derivative contracts. Under these master netting agreements, net settlement generally permits the Company or the counterparty to determine the net amount payable for contracts due on the same date and in the same currency for similar types of derivative transactions. The master netting agreements generally also provide for net settlement of all outstanding contracts with a counterparty in the case of an event of default or a termination event. The Company does not offset fair value amounts for derivative instruments and fair value amounts recognized for the right to reclaim cash collateral. At September 25, 2021 and December 26, 2020, the Company had recorded restricted cash in other current assets of $2.9 million and $7.6 million, respectively, as collateral related to open derivative contracts under the master netting arrangements. Long-Term Debt The fair value of long-term debt at September 25, 2021 approximates the carrying value on that date. The estimated fair values were determined based on quoted market prices and the current rates offered for debt with similar terms and maturities. The fair value of long-term debt is classified as level 2 within the fair value hierarchy. This classification is defined as a fair value determined using market-based inputs other than quoted prices that are observable for the liability, either directly or indirectly. On March 31, 2021, the Company entered into a Credit Agreement to replace its prior credit agreement that would have matured on December 6, 2021. The Company's total borrowing capacity under the Credit Agreement is $500.0 million. The Credit Agreement provides for an unsecured $400.0 million revolving credit facility, which matures March 31, 2026, and a term loan facility of $100.0 million, which matures March 31, 2022. Funds borrowed under the Credit Agreement may be used by the Company for working capital purposes and other general corporate purposes. In addition, the Credit Agreement provides a sublimit of $50.0 million for the issuance of letters of credit, a sublimit of $35.0 million for loans and letters of credit made in certain foreign currencies, and a Swing Line sublimit of $25.0 million. Outstanding letters of credit and foreign currency loans reduce borrowing availability under the Credit Agreement on a dollar-for-dollar basis. Total borrowings under the Credit Agreement were $120.0 million as of September 25, 2021. On October 6, 2021, the Company paid the term loan facility in full with borrowings under the revolving credit facility. During the first quarter of 2021, the Company announced the redemption of its Subordinated Debentures due 2027. The full redemption of outstanding debentures occurred on April 15, 2021 for a total of $291.4 million in principal plus accrued interest and a redemption premium of $5.7 million that was expensed during the second quarter.

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	9 Months Ended
	Sep. 25, 2021
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	Investments in Unconsolidated Affiliates On September 2, 2021, the Company acquired a 17 percent noncontrolling equity interest in a limited liability company in the retail distribution business by contributing the outstanding common stock of Die-Mold in exchange for the equity method interest. The transaction was recorded as a deconsolidation of a subsidiary and the recognition of an equity method investment at fair value, as described in “ Note 3 - Acquisitions and Dispositions .” This investment is recorded using the equity method of accounting. The Company records its proportionate share of the investees’ net income or loss one month in arrears as income (loss) from unconsolidated affiliates in the Condensed Consolidated Statements of Income. Tecumseh The Company owns a 50 percent interest in an unconsolidated affiliate that acquired Tecumseh Products Company LLC (Tecumseh). The Company also owns a 50 percent interest in a second unconsolidated affiliate that provides financing to Tecumseh. These investments are recorded using the equity method of accounting, as the Company can exercise significant influence but does not own a majority equity interest or otherwise control the respective entities. Under the equity method of accounting, these investments are stated at initial cost and are adjusted for subsequent additional investments and the Company’s proportionate share of earnings or losses and distributions. The Company records its proportionate share of the investees’ net income or loss, net of foreign taxes, one quarter in arrears as income (loss) from unconsolidated affiliates, net of foreign tax, in the Condensed Consolidated Statements of Income and its proportionate share of the investees’ other comprehensive income (loss), net of income taxes, in the Condensed Consolidated Statements of Comprehensive Income and the Condensed Consolidated Statements of Changes in Equity. The U.S. tax effect of the Company’s proportionate share of Tecumseh’s income or loss is recorded in income tax expense in the Condensed Consolidated Statements of Income. In general, the equity investment in unconsolidated affiliates is equal to the current equity investment plus the investees’ net accumulated losses. The following tables present summarized financial information derived from the Company’s equity method investees’ combined consolidated financial statements, which are prepared in accordance with U.S. GAAP. (In thousands) September 25, December 26, Current assets $ 217,520 $ 167,451 Noncurrent assets 82,069 78,241 Current liabilities 167,721 120,202 Noncurrent liabilities 49,367 50,020 For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Net sales $ 125,581 $ 73,850 $ 326,744 $ 284,398 Gross profit 15,693 7,565 40,715 32,073 Net income (loss) 5,599 (10,916) 262 (40,883) The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter and nine months ended September 25, 2021 included net income of $2.8 million and $0.1 million, respectively, for Tecumseh. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter and nine months ended September 26, 2020 included net losses of $5.5 million and $20.4 million, respectively, for Tecumseh. Mueller Middle East On December 30, 2015, the Company entered into a joint venture agreement with Cayan Ventures and Bahrain Mumtalakat Holding Company to build a copper tube mill in Bahrain. The business operates and brands its products under the Mueller Industries family of brands. The Company has invested approximately $5.0 million of cash to date and is the technical and marketing lead with a 40 percent ownership in the joint venture.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 25, 2021
Retirement Benefits [Abstract]
Benefit Plans	Benefit Plans The Company sponsors several qualified and nonqualified pension plans and other postretirement benefit plans for certain of its employees. The components of net periodic benefit cost (income) are as follows: For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Pension benefits: Interest cost $ 313 $ 862 $ 939 $ 2,586 Expected return on plan assets (903) (1,496) (2,711) (4,486) Amortization of net loss 378 494 1,135 1,482 Net periodic benefit income $ (212) $ (140) $ (637) $ (418) Other benefits: Service cost $ 64 $ 59 $ 194 $ 176 Interest cost 87 106 261 321 Amortization of prior service credit (118) (117) (353) (401) Amortization of net gain (32) (50) (96) (150) Curtailment gain — $ — — $ (2,591) Net periodic benefit cost (income) $ 1 $ (2) $ 6 $ (2,645) The components of net periodic benefit cost (income) other than the service cost component are included in other income, net in the Condensed Consolidated Statements of Income.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 25, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in certain litigation as a result of claims that arose in the ordinary course of business, which management believes will not have a material adverse effect on the Company’s financial position, results of operations, or cash flows. The Company may also realize the benefit of certain legal claims and litigation in the future; these gain contingencies are not recognized in the Condensed Consolidated Financial Statements. Environmental Non-operating Properties Southeast Kansas Sites The Kansas Department of Health and Environment (KDHE) has contacted the Company regarding environmental contamination at three former smelter sites in Kansas (Altoona, East La Harpe, and Lanyon). The Company is not a successor to the companies that operated these smelter sites, but is exploring possible settlement with KDHE and other potentially responsible parties (PRP) in order to avoid litigation. Altoona. Another PRP conducted a site investigation of the Altoona site under a consent decree with KDHE and submitted a removal site evaluation report recommending a remedy. The remedial design plan, which covers both on-site and certain off-site cleanup costs, was approved by the KDHE in 2016. Construction of the remedy was completed in 2018. East La Harpe. At the East La Harpe site, the Company and two other PRPs conducted a site study evaluation under KDHE supervision and prepared a site cleanup plan approved by KDHE. In 2016, the corporate parent (Peabody Energy) of a third party that the Company understands may owe indemnification obligations to one of the other PRPs (Blue Tee) in connection with the East La Harpe site filed for protection under Chapter 11 of the U.S. Bankruptcy Code. KDHE has extended the deadline for the PRPs to develop a repository design plan to allow for wetlands permitting to take place. In December 2018, KDHE provided a draft agreement which contemplates the use of funds KDHE obtained from two other parties (Peabody Energy and Blue Tee) to fund part of the remediation, and removes Blue Tee from the PRPs’ agreement with KDHE. The Company is currently negotiating the terms of that draft agreement. Lanyon. With respect to the Lanyon Site, in 2016, the Company received a general notice letter from the United States Environmental Protection Agency (EPA) asserting that the Company is a PRP, which the Company has denied. EPA issued an interim record of decision in 2017 and has been remediating properties at the site. The Company’s reserve for its proportionate share of the remediation costs associated with these three Southeast Kansas sites is $5.6 million. Shasta Area Mine Sites Mining Remedial Recovery Company (MRRC), a wholly owned subsidiary, owns certain inactive mines in Shasta County, California. MRRC has continued a program, begun in the late 1980s, of implementing various remedial measures, including sealing mine portals with concrete plugs in portals that were discharging water. The sealing program achieved significant reductions in the metal load in discharges from these adits; however, additional reductions are required pursuant to an order issued by the California Regional Water Quality Control Board (QCB). In response to a 1996 QCB Order, MRRC completed a feasibility study in 1997 describing measures designed to mitigate the effects of acid rock drainage. In December 1998, the QCB modified the 1996 order extending MRRC’s time to comply with water quality standards. In September 2002, the QCB adopted a new order requiring MRRC to adopt Best Management Practices (BMP) to control discharges of acid mine drainage, and again extended the time to comply with water quality standards until September 2007. During that time, implementation of BMP further reduced impacts of acid rock drainage; however, full compliance has not been achieved. The QCB is presently renewing MRRC’s discharge permit and will concurrently issue a new order. It is expected that the new 10-year permit will include an order requiring continued implementation of BMP through 2030 to address residual discharges of acid rock drainage. The Company currently estimates that it will spend between approximately $13.9 million and $18.0 million for remediation at these sites over the next 30 years and has accrued a reserve at the low end of this range. Lead Refinery Site U.S.S. Lead Refinery, Inc. (Lead Refinery), a non-operating wholly owned subsidiary of MRRC, has conducted corrective action and interim remedial activities (collectively, Site Activities) at Lead Refinery’s East Chicago, Indiana site pursuant to the Resource Conservation and Recovery Act since December 1996. Although the Site Activities have been substantially concluded, Lead Refinery is required to perform monitoring and maintenance-related activities pursuant to a post-closure permit issued by the Indiana Department of Environmental Management effective as of March 2, 2013. Approximate costs to comply with the post-closure permit, including associated general and administrative costs, are estimated at between $1.7 million and $2.4 million over the next 16 years. The Company has recorded a reserve at the low end of this range. On April 9, 2009, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the U.S. Environmental Protection Agency (EPA) added the Lead Refinery site and surrounding properties to the National Priorities List (NPL). On July 17, 2009, Lead Refinery received a written notice from the EPA indicating that it may be a PRP under CERCLA due to the release or threat of release of hazardous substances including lead into properties surrounding the Lead Refinery NPL site. The EPA identified two other PRPs in connection with that matter. In November 2012, the EPA adopted a remedy for the surrounding properties and in September 2014, the EPA announced that it had entered into a settlement with the two other PRPs whereby they will pay approximately $26.0 million to fund the cleanup of approximately 300 properties surrounding the Lead Refinery NPL site (zones 1 and 3 of operable unit 1) and perform certain remedial action tasks. On November 8, 2016, the Company, its subsidiary Arava Natural Resources Company, Inc. (Arava), and Arava’s subsidiary MRRC each received general notice letters from the EPA asserting that they may be PRPs in connection with the Lead Refinery NPL site. The Company, Arava, and MRRC have denied liability for any remedial action and response costs associated with the Lead Refinery NPL site. In June 2017, the EPA requested that Lead Refinery conduct, and the Company fund, a remedial investigation and feasibility study of operable unit 2 of the Lead Refinery NPL site pursuant to a proposed administrative settlement agreement and order on consent. The Company and Lead Refinery entered into that agreement in September 2017. The Company has made a capital contribution to Lead Refinery to conduct the remedial investigation and feasibility study with respect to operable unit 2 and has provided financial assurance in the amount of $1.0 million. The remedial investigation and feasibility study remain ongoing. The EPA has also asserted its position that Mueller is a responsible party for the Lead Refinery NPL site, and accordingly is responsible for a share of remedial action and response costs at the site and in the adjacent residential area. In January 2018, the EPA issued two unilateral administrative orders (UAOs) directing the Company, Lead Refinery, and four other PRPs to conduct soil and interior remediation of certain residences at the Lead Refinery NPL site (zones 2 and 3 of operable unit 1). The Company and Lead Refinery have reached agreement with the four other PRPs to implement these two UAOs, with the Company agreeing to pay, on an interim basis, (i) an estimated $4.5 million (subject to potential change through a future reallocation process) of the approximately $25.0 million the PRPs currently estimate it will cost to implement the UAOs, which estimate is subject to change, and (ii) $2.0 million relating to past costs incurred by other PRPs for work conducted at the site, as well as the possibility of up to $0.7 million in further payments for ongoing work by those PRPs. As of September 25, 2021, the Company has made payments of approximately $7.6 million related to the aforementioned agreement with the other PRPs. The Company disputes that it was properly named in the UAOs, and has reserved its rights to petition the EPA for reimbursement of any costs incurred to comply with the UAOs upon the completion of the work required therein. The Company and Lead Refinery are also evaluating entry into an administrative settlement agreement and order on consent with the EPA, along with the four other PRPs, which would involve payment of certain past and future costs relating to operable unit 1, in exchange for certain releases and contribution protection for the Company, Lead Refinery and their respective affiliates relating to that operable unit. The Company reserved $3.3 million for this settlement in the third quarter of 2021. In October 2017 and March 2018, separate groups of private plaintiffs sued the Company, Arava, MRRC, and Lead Refinery, along with other defendants, in two civil tort actions relating to the site. The Company, Arava, and MRRC have been voluntarily dismissed from both litigations without prejudice, and Lead Refinery’s motion to dismiss one of the matters was granted without prejudice. At this juncture, the Company is unable to determine the likelihood of a material adverse outcome or the amount or range of a potential loss in excess of the current reserve with respect to any remedial action or litigation relating to the Lead Refinery NPL site, either at Lead Refinery’s former operating site (operable unit 2) or the adjacent residential area (operable unit 1), including, but not limited to, EPA oversight costs for which the EPA may attempt to seek reimbursement from the Company, and past costs for which other PRPs may attempt to seek contribution from the Company. Bonita Peak Mining District Following an August 2015 spill from the Gold King Mine into the Animas River near Silverton, Colorado, the EPA listed the Bonita Peak Mining District on the NPL. Said listing was finalized in September 2016. The Bonita Peak Mining District encompasses 48 mining sites within the Animas River watershed, including the Sunnyside Mine, the American Tunnel, and the Sunbank Group. On or about July 25, 2017, Washington Mining Company (Washington Mining) (a wholly-owned subsidiary of the Company’s wholly-owned subsidiary, Arava), received a general notice letter from the EPA stating that Washington Mining may be a PRP under CERCLA in connection with the Bonita Peak Mining District site and therefore responsible for the remediation of certain portions of the site, along with related costs incurred by the EPA. Shortly thereafter, the Company received a substantively identical letter asserting that it may be a PRP at the site and similarly responsible for the cleanup of certain portions of the site. The general notice letters identify one other PRP at the site, and do not require specific action by Washington Mining or the Company at this time. At this juncture, the Company is unable to determine the likelihood of a materially adverse outcome or the amount or range of a potential loss with respect to any remedial action related to the Bonita Peak Mining District NPL site. Operating Properties Mueller Copper Tube Products, Inc. In 1999, Mueller Copper Tube Products, Inc. (MCTP), a wholly owned subsidiary, commenced a cleanup and remediation of soil and groundwater at its Wynne, Arkansas plant to remove trichloroethylene, a cleaning solvent formerly used by MCTP. On August 30, 2000, MCTP received approval of its Final Comprehensive Investigation Report and Storm Water Drainage Investigation Report addressing the treatment of soils and groundwater from the Arkansas Department of Environmental Quality (ADEQ). The Company established a reserve for this project in connection with the acquisition of MCTP in 1998. Effective November 17, 2008, MCTP entered into a Settlement Agreement and Administrative Order by Consent to submit a Supplemental Investigation Work Plan (SIWP) and subsequent Final Remediation Work Plan (RWP) for the site. By letter dated January 20, 2010, ADEQ approved the SIWP as submitted, with changes acceptable to the Company. On December 16, 2011, MCTP entered into an amended Administrative Order by Consent to prepare and implement a revised RWP regarding final remediation for the Site. The remediation system was activated in February 2014. Costs to implement the work plans, including associated general and administrative costs, are estimated to approximate $0.9 million to $1.1 million over the next five years. The Company has recorded a reserve at the low end of this range. United States Department of Commerce Antidumping Review On December 24, 2008, the Department of Commerce (DOC) initiated an antidumping administrative review of the antidumping duty order covering circular welded non-alloy steel pipe and tube from Mexico for the November 1, 2007 through October 31, 2008 period of review. The DOC selected Mueller Comercial as a respondent in the review. On April 19, 2010, the DOC published the final results of the review and assigned Mueller Comercial an antidumping duty rate of 48.33 percent. On May 25, 2010, the Company appealed the final results to the U.S. Court of International Trade (CIT). On December 16, 2011, the CIT issued a decision remanding the Department’s final results. While the matter was still pending, the Company and the United States reached an agreement to settle the appeal. Subject to the conditions of the agreement, the Company anticipated that certain of its subsidiaries would incur antidumping duties on subject imports made during the period of review and, as such, established a reserve for this matter. After the lapse of the statutory period of time during which U.S. Customs and Border Protection (CBP) was required, but failed, to liquidate the entries at the settled rate, the Company released the reserve. Between October 30, 2015 and November 27, 2015, CBP sent a series of invoices to Southland Pipe Nipples Co., Inc. (Southland), requesting payment of approximately $3.0 million in duties and interest in connection with 795 import entries made during the November 1, 2007 through October 31, 2008 period. On January 26, 2016 and January 27, 2016, Southland filed protests with CBP in connection with these invoices, noting that CBP’s asserted claims were not made in accordance with applicable law, including statutory provisions governing deemed liquidation. The Company believes in the merits of the legal objections raised in Southland’s protests, and CBP’s response to Southland’s protests is currently pending. Given the procedural posture and issues raised by this legal dispute, the Company cannot estimate the amount of potential duty liability, if any, that may result from CBP’s asserted claims. Deepwater Horizon Economic and Property Damage Claim During 2020, Mueller Copper Tube Company, a wholly owned subsidiary of the Company, collected approximately $22.1 million related to its claim under the Deepwater Horizon Economic and Property Damage Settlement Program. The collected amount represents settlement proceeds received after the payment of fees and expenses. Guarantees Guarantees, in the form of letters of credit, are issued by the Company generally to assure the payment of insurance deductibles, certain retiree health benefits, and debt at certain unconsolidated affiliates. The terms of the guarantees are generally one year but are renewable annually as required. These letters are primarily backed by the Company’s revolving credit facility. The

Income Taxes

Income Taxes	9 Months Ended
	Sep. 25, 2021
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the third quarter of 2021 was 26 percent compared with 24 percent for the same period last year. The primary items impacting the effective tax rate for the third quarter of 2021 were increases related to the provision for state income taxes, net of the federal benefit, of $8.5 million and the effect of foreign tax rates higher than statutory tax rates and other foreign items of $5.6 million. These items were partially offset by $2.2 million of other items. The items impacting the effective tax rate for the third quarter of 2020 were the provision for state income taxes, net of the federal benefit, of $1.4 million and other items of $0.4 million. The Company’s effective tax rate for the first nine months of 2021 was 26 percent compared with 25 percent for the same period last year. The items impacting the effective tax rate for the first nine months of 2021 were primarily attributable to the provision for state income taxes, net of the federal benefit, of $16.3 million and the effect of foreign tax rates higher than statutory tax rates and other foreign items of $8.7 million. These items were partially offset by $2.5 million of other items. The items impacting the effective tax rate for the first nine months of 2020 were primarily related to the provision for state income taxes, net of the federal benefit, of $4.8 million, the effect of foreign tax rates higher than statutory tax rates of $1.7 million, and $0.6 million of other items. The Company files a consolidated U.S. federal income tax return and numerous consolidated and separate-company income tax returns in many state, local, and foreign jurisdictions. The statute of limitations is open for the Company’s federal tax returns for 2015 and 2017 and all subsequent years. The statutes of limitations for most state returns are open for 2017 and all subsequent years, and some state and foreign returns are also open for some earlier tax years due to differing statute periods. The Internal Revenue Service recently completed its audit of the Company’s 2015 and 2017 federal consolidated returns, which resulted in no material impact to the financial statements. While the Company believes that it is adequately reserved for possible audit adjustments, the final resolution of these examinations cannot be determined with certainty and could result in final settlements that differ from current estimates.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 25, 2021
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) AOCI includes certain foreign currency translation adjustments from those subsidiaries not using the U.S. dollar as their functional currency, net deferred gains and losses on certain derivative instruments accounted for as cash flow hedges, adjustments to pension and OPEB liabilities, and other comprehensive income attributable to unconsolidated affiliates. The following tables provide changes in AOCI by component, net of taxes and noncontrolling interests (amounts in parentheses indicate debits to AOCI): For the Nine Months Ended September 25, 2021 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 26, 2020 $ (37,339) $ 984 $ (17,203) $ (1,325) $ (54,883) Other comprehensive income (loss) before reclassifications 763 862 (98) 2,211 3,738 Amounts reclassified from AOCI — (1,584) 574 — (1,010) Net current-period other comprehensive income (loss) 763 (722) 476 2,211 2,728 Balance as of September 25, 2021 $ (36,576) $ 262 $ (16,727) $ 886 $ (52,155) For the Nine Months Ended September 26, 2020 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 28, 2019 $ (46,198) $ 476 $ (21,855) $ (1,193) $ (68,770) Other comprehensive loss before reclassifications (11,254) (5,082) (1,468) (564) (18,368) Amounts reclassified from AOCI — 5,274 753 — 6,027 Net current-period other comprehensive (loss) income (11,254) 192 (715) (564) (12,341) Balance as of September 26, 2020 $ (57,452) $ 668 $ (22,570) $ (1,757) $ (81,111) Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Affected line item Unrealized losses (gains) on derivative commodity contracts $ 1,077 $ (248) $ (2,612) $ 6,581 Cost of goods sold 187 68 1,028 (1,307) Income tax expense (benefit) $ 1,264 $ (180) $ (1,584) $ 5,274 Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 228 $ 327 $ 686 $ 931 Other income, net (37) (63) (112) (178) Income tax benefit $ 191 $ 264 $ 574 $ 753 Net of tax and noncontrolling interests

Recent Accounting Standards (Po

Recent Accounting Standards (Policies)	9 Months Ended
	Sep. 25, 2021
Accounting Changes and Error Corrections [Abstract]
Recently Adopted and Issued Accounting Standards	Adopted In October 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2020-10, Codification Improvements: An Amendment of the FASB Accounting Standards Codification . The ASU facilitates updates to the Accounting Standards Codification for technical corrections such as conforming amendments, clarifications to guidance, simplifications to wording or structure of guidance, and other minor improvements. The Company adopted the ASU during the first quarter of 2021 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 . The new guidance addresses accounting for the transition into and out of the equity method and measuring certain purchased options and forward contracts to acquire investments. The Company adopted the ASU during the first quarter of 2021 using a prospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In December 2019, the FASB issued ASU No. 2019-12, Income Taxes: Simplifying the Accounting for Income Taxes . The new guidance affects general principles within Topic 740, Income Taxes. The amendments of ASU 2019-12 are meant to simplify and reduce the cost of accounting for income taxes. The Company adopted the ASU during the first quarter of 2021 using a prospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. Issued In January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): An Amendment of the FASB Accounting Standards Codification. The new guidance was issued in response to concerns about structural risks of interbank offered rates, and, particularly, the risk of cessation of the London Interbank Offered Rate (LIBOR). Regulators in numerous jurisdictions around the world have undertaken reference rate reform initiatives to identify alternative reference rates that are more observable or transaction based and less susceptible to manipulation. The ASU is effective in 2021 but can be applied through December 31, 2022. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 25, 2021
Segment Reporting [Abstract]
Summary of Segment Information	Summarized segment information is as follows: For the Quarter Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 688,200 $ 182,245 $ 122,252 $ (10,449) $ 982,248 Cost of goods sold 506,703 158,822 89,175 (10,435) 744,265 Depreciation and amortization 5,547 1,661 2,484 1,176 10,868 Selling, general, and administrative expense 23,751 2,710 9,521 12,542 48,524 Gain on sale of businesses — — — (54,759) (54,759) Operating income 152,199 19,052 21,072 41,027 233,350 Interest expense (1,116) Other (expense) income, net (2,548) Income before income taxes $ 229,686 For the Quarter Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 409,414 $ 118,831 $ 97,604 $ (6,744) $ 619,105 Cost of goods sold 339,904 95,717 70,450 (5,291) 500,780 Depreciation and amortization 5,362 1,774 2,547 1,069 10,752 Selling, general, and administrative expense 19,285 2,992 6,451 9,618 38,346 Operating income 44,863 18,348 18,156 (12,140) 69,227 Interest expense (4,885) Other income, net 522 Income before income taxes $ 64,864 Segment information (continued): For the Nine Months Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,947,564 $ 527,137 $ 364,986 $ (26,699) $ 2,812,988 Cost of goods sold 1,515,335 455,112 269,560 (27,612) 2,212,395 Depreciation and amortization 17,272 5,098 7,866 3,521 33,757 Selling, general, and administrative expense 71,152 8,529 23,781 34,429 137,891 Gain on sale of businesses — — — (54,759) (54,759) Operating income 343,805 58,398 63,779 17,722 483,704 Interest expense (7,451) Redemption premium (5,674) Other income, net (1,288) Income before income taxes $ 469,291 For the Nine Months Ended September 26, 2020 ( In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,128,467 $ 338,652 $ 276,983 $ (21,910) $ 1,722,192 Cost of goods sold 931,339 285,788 206,083 (10,556) 1,412,654 Depreciation and amortization 16,517 5,771 7,770 2,830 32,888 Selling, general, and administrative expense 57,998 8,690 19,607 31,454 117,749 Litigation settlement, net — — — (21,933) (21,933) Operating income 122,613 38,403 43,523 (23,705) 180,834 Interest expense (15,237) Other income, net 3,634 Income before income taxes $ 169,231 The following table presents total assets attributable to each segment: (In thousands) September 25, 2021 December 26, 2020 Segment assets: Piping Systems $ 1,142,523 $ 977,937 Industrial Metals 186,040 152,683 Climate 244,603 258,668 General Corporate 155,371 139,280 $ 1,728,537 $ 1,528,568
Disaggregation of Revenue From Contracts with Customers	The following tables represent a disaggregation of revenue from contracts with customers, along with the reportable segment for each category: For the Quarter Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 555,161 $ — $ — $ 555,161 Brass rod and forgings — 143,788 — 143,788 OEM components, tube & assemblies 6,943 12,076 29,627 48,646 Valves and plumbing specialties 126,096 — — 126,096 Flex duct and other HVAC components — — 92,625 92,625 Other — 26,381 — 26,381 688,200 182,245 122,252 992,697 Intersegment sales (10,449) Net sales $ 982,248 For the Quarter Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 320,619 $ — $ — $ 320,619 Brass rod and forgings — 89,487 — 89,487 OEM components, tube & assemblies 7,402 11,215 35,957 54,574 Valves and plumbing specialties 81,393 — — 81,393 Flex duct and other HVAC components — — 61,647 61,647 Other — 18,129 — 18,129 409,414 118,831 97,604 625,849 Intersegment sales (6,744) Net sales $ 619,105 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 25, 2021 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,548,392 $ — $ — $ 1,548,392 Brass rod and forgings — 418,024 — 418,024 OEM components, tube & assemblies 23,954 35,819 111,143 170,916 Valves and plumbing specialties 375,218 — — 375,218 Flex duct and other HVAC components — — 253,843 253,843 Other — 73,294 — 73,294 1,947,564 527,137 364,986 2,839,687 Intersegment sales (26,699) Net sales $ 2,812,988 For the Nine Months Ended September 26, 2020 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings 878,764 — — 878,764 Brass rod and forgings — 253,647 — 253,647 OEM components, tube & assemblies 49,509 32,524 105,461 187,494 Valves and plumbing specialties 200,194 — — 200,194 Flex duct and other HVAC components — — 171,522 171,522 Other — 52,481 — 52,481 1,128,467 338,652 276,983 1,744,102 Intersegment sales (21,910) Net sales $ 1,722,192

Cash, Cash Equivalents, and R_2

Cash, Cash Equivalents, and Restricted Cash (Tables)	9 Months Ended
	Sep. 25, 2021
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	(In thousands) September 25, December 26, Cash & cash equivalents $ 104,789 $ 119,075 Restricted cash included within other current assets 3,259 8,198 Restricted cash included within other assets 103 103 Total cash, cash equivalents, and restricted cash $ 108,151 $ 127,376
Restrictions on Cash and Cash Equivalents	(In thousands) September 25, December 26, Cash & cash equivalents $ 104,789 $ 119,075 Restricted cash included within other current assets 3,259 8,198 Restricted cash included within other assets 103 103 Total cash, cash equivalents, and restricted cash $ 108,151 $ 127,376

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 25, 2021
Inventory Disclosure [Abstract]
Inventories	(In thousands) September 25, December 26, Raw materials and supplies $ 133,109 $ 85,927 Work-in-process 66,574 49,361 Finished goods 215,007 186,785 Valuation reserves (9,100) (7,071) Inventories $ 405,590 $ 315,002

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 25, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments Designated as Cash Flow Hedges Reflected in the Financial Statements	The following table summarizes the location and fair value of the derivative instruments and disaggregates the net derivative assets and liabilities into gross components on a contract-by-contract basis: Asset Derivatives Liability Derivatives Fair Value Fair Value (In thousands) Balance Sheet Location September 25, December 26, Balance Sheet Location September 25, December 26, Commodity contracts - gains Other current assets $ 671 $ 1,213 Other current liabilities $ 27 $ 68 Commodity contracts - losses Other current assets (559) (8) Other current liabilities (43) (5,863) Total derivatives (1) $ 112 $ 1,205 $ (16) $ (5,795) (1) Does not include the impact of cash collateral provided to counterparties.
Schedule of Fair Value Hedges	The following tables summarize the effects of derivative instruments on the Company’s Condensed Consolidated Statements of Income: For the Quarter Ended For the Nine Months Ended (In thousands) Location September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Undesignated derivatives: Gain (loss) on commodity contracts (nonqualifying) Cost of goods sold 7,282 843 (3,141) (3,596)
Summary of Activities Related to Derivative Instruments Classified as Cash Flow Hedges	The following tables summarize amounts recognized in and reclassified from AOCI during the period: For the Quarter Ended September 25, 2021 (In thousands) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss (Gain) Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 845 Cost of goods sold $ 1,265 Other 13 Other (1) Total $ 858 Total $ 1,264 Amounts recognized in and reclassified from AOCI (continued): For the Quarter Ended September 26, 2020 (In thousands) Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 337 Cost of goods sold $ (180) Other (6) Other — Total $ 331 Total $ (180) For the Nine Months Ended September 25, 2021 (In thousands) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Gain Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ 861 Cost of goods sold $ (1,584) Other 1 Other — Total $ 862 Total $ (1,584) For the Nine Months Ended September 26, 2020 (In thousands) (Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax Classification Gains (Losses) Loss Reclassified from AOCI (Effective Portion), Net of Tax Cash flow hedges: Commodity contracts $ (5,084) Cost of goods sold $ 5,273 Other 2 Other 1 Total $ (5,082) Total $ 5,274

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	9 Months Ended
	Sep. 25, 2021
Equity Method Investments and Joint Ventures [Abstract]
Summarized Financial Information Derived From the Company's Equity Method Investee's Consolidated Financial Statements	The following tables present summarized financial information derived from the Company’s equity method investees’ combined consolidated financial statements, which are prepared in accordance with U.S. GAAP. (In thousands) September 25, December 26, Current assets $ 217,520 $ 167,451 Noncurrent assets 82,069 78,241 Current liabilities 167,721 120,202 Noncurrent liabilities 49,367 50,020 For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Net sales $ 125,581 $ 73,850 $ 326,744 $ 284,398 Gross profit 15,693 7,565 40,715 32,073 Net income (loss) 5,599 (10,916) 262 (40,883)

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 25, 2021
Retirement Benefits [Abstract]
Components of Net Periodic Benefit Cost (Income)	The components of net periodic benefit cost (income) are as follows: For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Pension benefits: Interest cost $ 313 $ 862 $ 939 $ 2,586 Expected return on plan assets (903) (1,496) (2,711) (4,486) Amortization of net loss 378 494 1,135 1,482 Net periodic benefit income $ (212) $ (140) $ (637) $ (418) Other benefits: Service cost $ 64 $ 59 $ 194 $ 176 Interest cost 87 106 261 321 Amortization of prior service credit (118) (117) (353) (401) Amortization of net gain (32) (50) (96) (150) Curtailment gain — $ — — $ (2,591) Net periodic benefit cost (income) $ 1 $ (2) $ 6 $ (2,645)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 25, 2021
Equity [Abstract]
Changes in AOCI by Component, Net of Taxes and Noncontrolling Interest	The following tables provide changes in AOCI by component, net of taxes and noncontrolling interests (amounts in parentheses indicate debits to AOCI): For the Nine Months Ended September 25, 2021 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 26, 2020 $ (37,339) $ 984 $ (17,203) $ (1,325) $ (54,883) Other comprehensive income (loss) before reclassifications 763 862 (98) 2,211 3,738 Amounts reclassified from AOCI — (1,584) 574 — (1,010) Net current-period other comprehensive income (loss) 763 (722) 476 2,211 2,728 Balance as of September 25, 2021 $ (36,576) $ 262 $ (16,727) $ 886 $ (52,155) For the Nine Months Ended September 26, 2020 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 28, 2019 $ (46,198) $ 476 $ (21,855) $ (1,193) $ (68,770) Other comprehensive loss before reclassifications (11,254) (5,082) (1,468) (564) (18,368) Amounts reclassified from AOCI — 5,274 753 — 6,027 Net current-period other comprehensive (loss) income (11,254) 192 (715) (564) (12,341) Balance as of September 26, 2020 $ (57,452) $ 668 $ (22,570) $ (1,757) $ (81,111)
Reclassification Adjustments Out of AOCI	Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI For the Quarter Ended For the Nine Months Ended (In thousands) September 25, 2021 September 26, 2020 September 25, 2021 September 26, 2020 Affected line item Unrealized losses (gains) on derivative commodity contracts $ 1,077 $ (248) $ (2,612) $ 6,581 Cost of goods sold 187 68 1,028 (1,307) Income tax expense (benefit) $ 1,264 $ (180) $ (1,584) $ 5,274 Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 228 $ 327 $ 686 $ 931 Other income, net (37) (63) (112) (178) Income tax benefit $ 191 $ 264 $ 574 $ 753 Net of tax and noncontrolling interests

Earnings per Common Share (Deta

Earnings per Common Share (Details) - shares shares in Thousands	3 Months Ended
	Sep. 25, 2021	Sep. 26, 2020
Earnings Per Share [Abstract]
Stock-based awards excluded from computation of diluted earnings per share (in shares)	30	3

Acquisitions and Dispositions -

Acquisitions and Dispositions - Narrative (Details) - USD ($) $ in Millions	Sep. 02, 2021	Jan. 29, 2021	Aug. 03, 2020	Jan. 17, 2020	Sep. 25, 2021	Jun. 26, 2021	Mar. 27, 2021	Sep. 25, 2021	Sep. 26, 2020	Jul. 28, 2021
Die-Mold | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Consideration for sale of businesses	$ 24
Net sales of disposed of business								$ 10.9	$ 10.4
Net income of disposed business								1.6	1.4
Gain (loss) on disposal of businesses	$ 4.7
Fabricated Tube Products and Shoals Tubular, Inc. | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Business Acquisition [Line Items]
Consideration for sale of businesses										$ 78.2
Net sales of disposed of business								37	38.3
Net income of disposed business								5.5	$ 4.8
Assets of disposed business										31.7
Liabilities of disposed business										$ 3.6
Gain (loss) on disposal of businesses								$ 50.1
Hart & Cooley Flexible Duct Business
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments		$ 15.3
Cash portion of acquisition price		14
Payment for contingent consideration		1.3
Fair value of assets acquired		15.3
Fair value of property, plant and equipment acquired		10.8
Fair value of inventories acquired		4.5
Tax-deductible goodwill		$ 0.1
Increase (decrease) in property plant and equipment					$ 2.4
Increase (decrease) in goodwill					1
Recognition of contingent consideration					$ 1.4
Wieland-Kessler LLC
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments			$ 57.2
Fair value of assets acquired			27.3
Tax-deductible goodwill			$ 29.9
Increase (decrease) in property plant and equipment						$ (1.4)
Increase (decrease) in goodwill						$ 1.4	$ (1.5)
Increase in intangible assets							$ 1.5
Shoals Tubular, Inc.
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments				$ 15.3
Cash portion of acquisition price				15.3
Fair value of assets acquired				6.2
Fair value of property, plant and equipment acquired				3.7
Fair value of inventories acquired				1.8
Tax-deductible goodwill				9.3
Fair value of accounts receivable acquired				0.7
Fair value of liabilities acquired				$ 0.2
Retail Distribution Business
Business Acquisition [Line Items]
Ownership interest acquired (as a percent)	17.00%

Segment Information - Summary o

Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 25, 2021	Jun. 26, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Dec. 26, 2020
Summary of segment information [Abstract]
Net sales	$ 982,248		$ 619,105	$ 2,812,988	$ 1,722,192
Cost of goods sold	744,265		500,780	2,212,395	1,412,654
Depreciation and amortization	10,868		10,752	33,757	32,888
Selling, general, and administrative expense	48,524		38,346	137,891	117,749
Gain on sale of businesses	(54,759)		0	(54,759)	0
Litigation settlement, net	0		0	0	(21,933)
Operating income	233,350		69,227	483,704	180,834
Interest expense	(1,116)		(4,885)	(7,451)	(15,237)
Redemption premium	0	$ (5,700)	0	(5,674)	0
Other income (expense), net	(2,548)		522	(1,288)	3,634
Income before income taxes	229,686		64,864	469,291	169,231
Assets	1,728,537			1,728,537		$ 1,528,568
Operating Segments
Summary of segment information [Abstract]
Net sales	992,697		625,849	2,839,687	1,744,102
Operating Segments | Piping Systems
Summary of segment information [Abstract]
Net sales	688,200		409,414	1,947,564	1,128,467
Cost of goods sold	506,703		339,904	1,515,335	931,339
Depreciation and amortization	5,547		5,362	17,272	16,517
Selling, general, and administrative expense	23,751		19,285	71,152	57,998
Gain on sale of businesses	0			0
Litigation settlement, net					0
Operating income	152,199		44,863	343,805	122,613
Assets	1,142,523			1,142,523		977,937
Operating Segments | Industrial Metals
Summary of segment information [Abstract]
Net sales	182,245		118,831	527,137	338,652
Cost of goods sold	158,822		95,717	455,112	285,788
Depreciation and amortization	1,661		1,774	5,098	5,771
Selling, general, and administrative expense	2,710		2,992	8,529	8,690
Gain on sale of businesses	0			0
Litigation settlement, net					0
Operating income	19,052		18,348	58,398	38,403
Assets	186,040			186,040		152,683
Operating Segments | Climate
Summary of segment information [Abstract]
Net sales	122,252		97,604	364,986	276,983
Cost of goods sold	89,175		70,450	269,560	206,083
Depreciation and amortization	2,484		2,547	7,866	7,770
Selling, general, and administrative expense	9,521		6,451	23,781	19,607
Gain on sale of businesses	0			0
Litigation settlement, net					0
Operating income	21,072		18,156	63,779	43,523
Assets	244,603			244,603		258,668
Corporate and Eliminations
Summary of segment information [Abstract]
Net sales	(10,449)		(6,744)	(26,699)	(21,910)
Cost of goods sold	(10,435)		(5,291)	(27,612)	(10,556)
Depreciation and amortization	1,176		1,069	3,521	2,830
Selling, general, and administrative expense	12,542		9,618	34,429	31,454
Gain on sale of businesses	(54,759)			(54,759)
Litigation settlement, net					(21,933)
Operating income	41,027		$ (12,140)	17,722	$ (23,705)
Assets	$ 155,371			$ 155,371		$ 139,280

Segment Information - Net Sales

Segment Information - Net Sales by Major Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 982,248	$ 619,105	$ 2,812,988	$ 1,722,192
Operating Segments
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	992,697	625,849	2,839,687	1,744,102
Operating Segments | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	688,200	409,414	1,947,564	1,128,467
Operating Segments | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	182,245	118,831	527,137	338,652
Operating Segments | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	122,252	97,604	364,986	276,983
Operating Segments | Tube and fittings
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	555,161	320,619	1,548,392	878,764
Operating Segments | Tube and fittings | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	555,161	320,619	1,548,392	878,764
Operating Segments | Tube and fittings | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Tube and fittings | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Brass rod and forgings
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	143,788	89,487	418,024	253,647
Operating Segments | Brass rod and forgings | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Brass rod and forgings | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	143,788	89,487	418,024	253,647
Operating Segments | Brass rod and forgings | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | OEM components, tube & assemblies
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	48,646	54,574	170,916	187,494
Operating Segments | OEM components, tube & assemblies | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	6,943	7,402	23,954	49,509
Operating Segments | OEM components, tube & assemblies | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	12,076	11,215	35,819	32,524
Operating Segments | OEM components, tube & assemblies | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	29,627	35,957	111,143	105,461
Operating Segments | Valves and plumbing specialties
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	126,096	81,393	375,218	200,194
Operating Segments | Valves and plumbing specialties | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	126,096	81,393	375,218	200,194
Operating Segments | Valves and plumbing specialties | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Valves and plumbing specialties | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Flex duct and other HVAC components
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	92,625	61,647	253,843	171,522
Operating Segments | Flex duct and other HVAC components | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Flex duct and other HVAC components | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Flex duct and other HVAC components | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	92,625	61,647	253,843	171,522
Operating Segments | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	26,381	18,129	73,294	52,481
Operating Segments | Other | Piping Systems
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments | Other | Industrial Metals
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	26,381	18,129	73,294	52,481
Operating Segments | Other | Climate
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Intersegment sales
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ (10,449)	$ (6,744)	$ (26,699)	$ (21,910)

Cash, Cash Equivalents, and R_3

Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 25, 2021	Dec. 26, 2020	Sep. 26, 2020	Dec. 28, 2019
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 104,789	$ 119,075
Restricted cash included within other current assets	3,259	8,198
Restricted cash included within other assets	103	103
Total cash, cash equivalents, and restricted cash	$ 108,151	$ 127,376	$ 114,379	$ 98,042

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 25, 2021	Dec. 26, 2020
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 133,109	$ 85,927
Work-in-process	66,574	49,361
Finished goods	215,007	186,785
Valuation reserves	(9,100)	(7,071)
Inventories	$ 405,590	$ 315,002

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - USD ($)	Apr. 15, 2021	Sep. 25, 2021	Jun. 26, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Mar. 31, 2021	Dec. 26, 2020
Derivative [Line Items]
Restricted cash in other current assets as collateral related to open derivative contracts		$ 2,900,000			$ 2,900,000			$ 7,600,000
Redemption premium		0	$ (5,700,000)	$ 0	(5,674,000)	$ 0
Line of Credit
Derivative [Line Items]
Maximum borrowing capacity							$ 500,000,000
Total borrowing capacity		120,000,000			120,000,000
Line of Credit | Revolving Credit Facility
Derivative [Line Items]
Maximum borrowing capacity							400,000,000
Line of Credit | Term Loan Facility
Derivative [Line Items]
Maximum borrowing capacity							100,000,000
Line of Credit | Letter of Credit
Derivative [Line Items]
Maximum borrowing capacity							50,000,000
Line of Credit | Bridge Loan
Derivative [Line Items]
Maximum borrowing capacity							25,000,000
Foreign Line of Credit | Letter of Credit
Derivative [Line Items]
Maximum borrowing capacity							$ 35,000,000
Subordinated Debt
Derivative [Line Items]
Repayments of debt	$ 291,400,000
Commodity Contracts
Derivative [Line Items]
Deferred net gains (losses), net of tax, included in AOCI		142,000			142,000
Cash Flow Hedging | Commodity Contracts | Long
Derivative [Line Items]
Open option contracts written, at fair value		46,900,000			$ 46,900,000
Time period for open copper future contract purchases					18 months
Fair value of future contracts with net gain (loss) position					$ 112,000
Fair Value Hedging | Commodity Contracts | Short
Derivative [Line Items]
Fair value of future contracts with net gain (loss) position					(16,000)
Open future contracts to sell copper		$ 867,000			$ 867,000
Time period for open copper future contract sales					10 months

Financial Instruments - Summary

Financial Instruments - Summary of Location and Fair Value (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 25, 2021	Dec. 26, 2020
Derivatives, Fair Value [Line Items]
Total derivative assets	$ 112	$ 1,205
Total derivative liabilities	(16)	(5,795)
Other current assets | Commodity Contracts
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	671	1,213
Other current assets: Loss positions	(559)	(8)
Other current liabilities | Commodity Contracts
Derivatives, Fair Value [Line Items]
Other current liability: Gain positions	27	68
Other current liability: Loss positions	$ (43)	$ (5,863)

Financial Instruments - Effects

Financial Instruments - Effects of Derivative Instruments on Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Commodity Contracts | Cost of goods sold | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on commodity contracts (nonqualifying)	$ 7,282	$ 843	$ (3,141)	$ (3,596)

Financial Instruments - Amounts

Financial Instruments - Amounts Recognized in and Reclassified from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in AOCI (Effective Portion), Net of Tax	$ 2,122	$ 151	$ (722)	$ 192
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in AOCI (Effective Portion), Net of Tax	858	331	862	(5,082)
Gain Reclassified from AOCI (Effective Portion), Net of Tax	1,264	(180)	1,584	(5,274)
Commodity Contracts | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in AOCI (Effective Portion), Net of Tax	845	337	861	(5,084)
Commodity Contracts | Cash Flow Hedging | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Gain Reclassified from AOCI (Effective Portion), Net of Tax	1,265	(180)	1,584	(5,273)
Other | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain Recognized in AOCI (Effective Portion), Net of Tax	13	(6)	1	2
Gain Reclassified from AOCI (Effective Portion), Net of Tax	$ (1)	$ 0	$ 0	$ (1)

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		66 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Jun. 26, 2021	Sep. 02, 2021
Schedule of Equity Method Investments [Line Items]
Net income (loss)	$ 172,256	$ 43,957	$ 348,426	$ 106,395
Retail Distribution Business
Schedule of Equity Method Investments [Line Items]
Ownership interest acquired (as a percent)						17.00%
Tecumseh Products Holdings LLC
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50.00%		50.00%
Net income (loss)	$ 2,800	$ (5,500)	$ 100	$ (20,400)
Second Unconsolidated Affiliate
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50.00%		50.00%
Mueller Middle East
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	40.00%		40.00%
Cash invested to acquire joint venture interest					$ 5,000

Investments in Unconsolidated_4

Investments in Unconsolidated Affiliates - Summarized Financial Information Derived from Equity Method Investees' Consolidated Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Dec. 26, 2020
Balance sheet data [Abstract]
Current assets	$ 1,037,943		$ 1,037,943		$ 825,361
Current liabilities	380,098		380,098		339,643
Income Statement [Abstract]
Net sales	982,248	$ 619,105	2,812,988	$ 1,722,192
Net income (loss)	172,256	43,957	348,426	106,395
Tecumseh
Balance sheet data [Abstract]
Current assets	217,520		217,520		167,451
Noncurrent assets	82,069		82,069		78,241
Current liabilities	167,721		167,721		120,202
Noncurrent liabilities	49,367		49,367		$ 50,020
Income Statement [Abstract]
Net sales	125,581	73,850	326,744	284,398
Gross profit	15,693	7,565	40,715	32,073
Net income (loss)	$ 5,599	$ (10,916)	$ 262	$ (40,883)

Benefit Plans (Details)

Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Pension Benefits
Components of net periodic benefit cost (income) [Abstract]
Interest cost	$ 313	$ 862	$ 939	$ 2,586
Expected return on plan assets	(903)	(1,496)	(2,711)	(4,486)
Amortization of net loss (gain)	378	494	1,135	1,482
Net periodic benefit income	(212)	(140)	(637)	(418)
Other Benefits
Components of net periodic benefit cost (income) [Abstract]
Interest cost	87	106	261	321
Amortization of net loss (gain)	(32)	(50)	(96)	(150)
Service cost	64	59	194	176
Amortization of prior service credit	(118)	(117)	(353)	(401)
Curtailment gain	0	0	0	(2,591)
Net periodic benefit income	$ 1	$ (2)	$ 6	$ (2,645)

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	1 Months Ended		9 Months Ended	12 Months Ended
	Jan. 31, 2018USD ($)unilateral_administrative_orderpotentially_responsible_party	Nov. 27, 2015USD ($)	Sep. 25, 2021USD ($)propertypotentially_responsible_party	Oct. 31, 2008Import_entry	Sep. 25, 2021smelter_site	Sep. 25, 2021USD ($)	Dec. 26, 2020USD ($)	Jun. 30, 2018action	Nov. 08, 2016USD ($)	Apr. 19, 2010
Loss Contingencies [Line Items]
Term of guarantees			1 year
Payments required to be made under guarantees, maximum						$ 23.9
United States Department of Commerce Antidumping Review
Loss Contingencies [Line Items]
Assignment of antidumping duty rate on U.S. imports by Company subsidiaries (as a percent)										48.33%
Payment for interest and duties		$ 3
Number of import entries | Import_entry				795
Deepwater Horizon Economic and Property Damage Claim
Loss Contingencies [Line Items]
Amount awarded to the Company							$ 22.1
Lead Refinery Site
Loss Contingencies [Line Items]
Financial guarantee									$ 1
Lead Refinery NPL Site
Loss Contingencies [Line Items]
Environmental reserves	$ 4.5
Number of UAOs | unilateral_administrative_order	2
Number of PRPs | potentially_responsible_party	4
Site contingency, total costs	$ 25
Site contingency, amount agreed upon to pay PRPs for past costs	2
Site contingency, additional reimbursement of past costs	$ 0.7
Contingency charge			$ 7.6
Number of civil tort actions | action								2
Reserve for settlement						3.3
Non operating Properties | Southeast Kansas Sites
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations			2		3
Environmental reserves						$ 5.6
Non operating Properties | Shasta Area Mine Sites
Loss Contingencies [Line Items]
Period of permit, implementation of Best Management Practices			10 years
Estimated remediation costs, term			30 years
Non operating Properties | Lead Refinery Site
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations | potentially_responsible_party			2
Estimated remediation costs, term			16 years
Amount other PRPs will pay to fund cleanup			$ 26
Number of surrounding properties | property			300
Non operating Properties | Minimum | Shasta Area Mine Sites
Loss Contingencies [Line Items]
Estimated remediation costs			$ 13.9
Non operating Properties | Minimum | Lead Refinery Site
Loss Contingencies [Line Items]
Estimated remediation costs			1.7
Non operating Properties | Maximum | Shasta Area Mine Sites
Loss Contingencies [Line Items]
Estimated remediation costs			18
Non operating Properties | Maximum | Lead Refinery Site
Loss Contingencies [Line Items]
Estimated remediation costs			$ 2.4
Operating Properties | Mueller Copper Tube Products, Inc.
Loss Contingencies [Line Items]
Estimated remediation costs, term			5 years
Operating Properties | Minimum | Mueller Copper Tube Products, Inc.
Loss Contingencies [Line Items]
Estimated remediation costs			$ 0.9
Operating Properties | Maximum | Mueller Copper Tube Products, Inc.
Loss Contingencies [Line Items]
Estimated remediation costs			$ 1.1

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Income Tax Disclosure [Abstract]
Effective tax rate	26.00%	24.00%	26.00%	25.00%
Provision for state income taxes, net of federal benefits	$ 8.5	$ 1.4	$ 16.3	$ 4.8
Effect of foreign tax rates differential	5.6		8.7	1.7
Other items	$ 2.2	$ 0.4	$ 2.5	$ 0.6

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Changes in AOCI by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			$ 801,060
Total other comprehensive (loss) income, net	$ (4,977)	$ 9,640	1,298	$ (12,601)
Balance at end of period	1,126,232		1,126,232
Total
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	(48,262)	(89,799)	(54,883)	(68,770)
Other comprehensive income (loss) before reclassifications			3,738	(18,368)
Amounts reclassified from AOCI			(1,010)	6,027
Total other comprehensive (loss) income, net	(3,893)	8,688	2,728	(12,341)
Balance at end of period	(52,155)	(81,111)	(52,155)	(81,111)
Cumulative Translation Adjustment
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(37,339)	(46,198)
Other comprehensive income (loss) before reclassifications			763	(11,254)
Amounts reclassified from AOCI			0	0
Total other comprehensive (loss) income, net			763	(11,254)
Balance at end of period	(36,576)	(57,452)	(36,576)	(57,452)
Unrealized Gain (Loss) on Derivatives
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			984	476
Other comprehensive income (loss) before reclassifications			862	(5,082)
Amounts reclassified from AOCI			(1,584)	5,274
Total other comprehensive (loss) income, net			(722)	192
Balance at end of period	262	668	262	668
Pension/OPEB Liability Adjustment
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(17,203)	(21,855)
Other comprehensive income (loss) before reclassifications			(98)	(1,468)
Amounts reclassified from AOCI			574	753
Total other comprehensive (loss) income, net			476	(715)
Balance at end of period	(16,727)	(22,570)	(16,727)	(22,570)
Attributable to Unconsol. Affiliates
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(1,325)	(1,193)
Other comprehensive income (loss) before reclassifications			2,211	(564)
Amounts reclassified from AOCI			0	0
Total other comprehensive (loss) income, net			2,211	(564)
Balance at end of period	$ 886	$ (1,757)	$ 886	$ (1,757)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Reclassification Adjustments Out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	$ 60,229	$ 15,450	$ 120,996	$ 42,623
Net of tax and noncontrolling interests	(170,980)	(42,702)	(342,919)	(103,073)
Other income, net	2,548	(522)	1,288	(3,634)
Unrealized losses (gains) on derivative commodity contracts | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	1,077	(248)	(2,612)	6,581
Income tax expense (benefit)	187	68	1,028	(1,307)
Net of tax and noncontrolling interests	1,264	(180)	(1,584)	5,274
Amortization of net loss and prior service cost on employee benefit plans | Amount Reclassified from AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)	(37)	(63)	(112)	(178)
Net of tax and noncontrolling interests	191	264	574	753
Other income, net	$ 228	$ 327	$ 686	$ 931