Mueller Industries (MLI) 10-Q 21 Oct 20 2020 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 26, 2020	Oct. 16, 2020
Cover [Abstract]
Document Quarterly Report	true
Document Type	10-Q
Document Period End Date	Sep. 26, 2020
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		57,080,225
Entity Central Index Key	0000089439
Current Fiscal Year End Date	--12-26
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Document Transition Report	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Income Statement [Abstract]
Net sales	$ 619,105	$ 608,602	$ 1,722,192	$ 1,886,777
Cost of goods sold	500,780	510,788	1,412,654	1,586,129
Depreciation and amortization	10,752	10,823	32,888	31,856
Selling, general, and administrative expense	38,346	40,739	114,714	121,838
Asset impairments	0	0	3,035	0
Litigation settlement, net	0	0	(21,933)	0
Operating income	69,227	46,252	180,834	146,954
Interest expense	(4,885)	(6,148)	(15,237)	(20,135)
Other income, net	522	533	3,634	823
Income before income taxes	64,864	40,637	169,231	127,642
Income tax expense	(15,450)	(7,665)	(42,623)	(27,643)
Loss from unconsolidated affiliates, net of foreign tax	(5,457)	(2,528)	(20,213)	(23,740)
Consolidated net income	43,957	30,444	106,395	76,259
Net income attributable to noncontrolling interests	(1,255)	(1,351)	(3,322)	(3,457)
Net income attributable to Mueller Industries, Inc.	$ 42,702	$ 29,093	$ 103,073	$ 72,802
Weighted average shares for basic earnings per share (in shares)	55,816	55,832	55,805	55,771
Effect of dilutive stock-based awards (in shares)	550	482	534	523
Adjusted weighted average shares for diluted earnings per share (in shares)	56,366	56,314	56,339	56,294
Basic earnings per share (in dollars per share)	$ 0.77	$ 0.52	$ 1.85	$ 1.31
Diluted earnings per share (in dollars per share)	0.76	0.52	1.83	1.29
Dividends per share (in dollars per share)	$ 0.10	$ 0.10	$ 0.30	$ 0.30

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 43,957	$ 30,444	$ 106,395	$ 76,259
Other comprehensive income (loss), net of tax:
Foreign currency translation	9,320	(6,692)	(11,514)	(3,612)
Net change with respect to derivative instruments and hedging activities, net of tax of $(43), $56, $(53), and $(34)	151	(195)	192	133
Net change in pension and postretirement obligation adjustments, net of tax of $92, $(232), $224, and $(323)	(170)	777	(715)	1,207
Attributable to unconsolidated affiliates, net of tax of $(99), $(159), $163, and $(240)	339	547	(564)	828
Total other comprehensive income (loss), net	9,640	(5,563)	(12,601)	(1,444)
Consolidated comprehensive income	53,597	24,881	93,794	74,815
Comprehensive income attributable to noncontrolling interests	(2,207)	(857)	(3,062)	(2,044)
Comprehensive income attributable to Mueller Industries, Inc.	$ 51,390	$ 24,024	$ 90,732	$ 72,771

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Statement of Comprehensive Income [Abstract]
Net change with respect to derivative instruments and hedging activities, tax (expense) benefit	$ (43)	$ 56	$ (53)	$ (34)
Net actuarial loss on pension and postretirement obligations, tax benefit (expense)	92	(232)	224	(323)
Attributable to unconsolidated affiliates, tax benefit (expense)	$ (99)	$ (159)	$ 163	$ (240)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Current assets:
Cash and cash equivalents	$ 113,640	$ 97,944
Accounts receivable, less allowance for doubtful accounts of $1,289 in 2020 and $770 in 2019	320,035	269,943
Inventories	271,310	292,107
Other current assets	24,880	33,778
Total current assets	729,865	693,772
Property, plant, and equipment, net	368,736	363,128
Operating lease right-of-use assets	22,397	26,922
Goodwill, net	185,479	153,276
Intangible assets, net	62,474	60,082
Investments in unconsolidated affiliates	27,423	48,363
Other assets	23,638	25,397
Total assets	1,420,012	1,370,940
Current liabilities:
Current portion of debt	6,684	7,530
Accounts payable	108,063	85,644
Accrued wages and other employee costs	49,016	41,673
Current portion of operating lease liabilities	6,320	5,250
Other current liabilities	82,669	94,190
Total current liabilities	252,752	234,287
Long-term debt, less current portion	342,972	378,724
Pension liabilities	5,773	9,126
Postretirement benefits other than pensions	12,413	13,082
Environmental reserves	19,809	19,972
Deferred income taxes	18,066	21,094
Noncurrent operating lease liabilities	16,464	22,388
Other noncurrent liabilities	12,412	10,131
Total liabilities	680,661	708,804
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 57,080,225 in 2020 and 56,949,246 in 2019	802	802
Additional paid-in capital	277,663	278,609
Retained earnings	988,983	903,070
Accumulated other comprehensive loss	(81,111)	(68,770)
Treasury common stock, at cost	(468,716)	(470,243)
Total Mueller Industries, Inc. stockholders' equity	717,621	643,468
Noncontrolling interests	21,730	18,668
Total equity	739,351	662,136
Total liabilities and equity	$ 1,420,012	$ 1,370,940

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,289	$ 770
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)	57,080,225	56,949,246

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash flows from operating activities
Consolidated net income	$ 106,395	$ 76,259
Reconciliation of consolidated net income to net cash provided by operating activities:
Depreciation and amortization	33,127	32,095
Stock-based compensation expense	6,332	6,355
Provision for doubtful accounts receivable	953	(66)
Loss from unconsolidated affiliates	20,213	23,740
Loss (gain) on disposals of properties	144	(24)
Impairment charges	3,035	0
Change in fair value of contingent consideration	0	4,500
Deferred income tax benefit	(836)	(1,593)
Changes in assets and liabilities, net of effects of business acquired:
Receivables	(45,530)	(47,367)
Inventories	41,598	50,985
Other assets	9,053	(7,485)
Current liabilities	25,913	1,687
Other liabilities	(5,813)	(7,112)
Other, net	2,294	(47)
Net cash provided by operating activities	196,878	131,927
Cash flows from investing activities
Capital expenditures	(29,204)	(20,162)
Acquisition of businesses, net of cash acquired	(72,648)	3,465
Investments in unconsolidated affiliates	0	(11,000)
Issuance of notes receivable	(9,155)	0
Proceeds from sales of assets	12	385
Net cash used in investing activities	(110,995)	(27,312)
Cash flows from financing activities
Dividends paid to stockholders of Mueller Industries, Inc.	(16,754)	(16,738)
Repurchase of common stock	(5,574)	(1,763)
Payment of contingent consideration	(7,000)	(3,170)
Issuance of long-term debt	150,027	100,658
Repayments of long-term debt	(186,492)	(151,305)
Repayment of debt by consolidated joint ventures, net	(299)	(4,352)
Net cash used to settle stock-based awards	(160)	(1,069)
Net cash used in financing activities	(66,252)	(77,739)
Effect of exchange rate changes on cash	(3,294)	(1,511)
Increase in cash, cash equivalents, and restricted cash	16,337	25,365
Cash, cash equivalents, and restricted cash at the beginning of the period	98,042	77,138
Cash, cash equivalents, and restricted cash at the end of the period	$ 114,379	$ 102,503

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Balance at beginning of period at Dec. 29, 2018		$ 802	$ 276,849	$ 824,737	$ (79,792)	$ (474,240)	$ 14,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive stock option plans			(624)			(445)
Stock-based compensation expense			6,355
Issuance of restricted stock			(6,382)			6,382
Net income attributable to Mueller Industries, Inc.	$ 72,802			72,802
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(17,002)
Total other comprehensive income (loss) attributable to Mueller Industries, Inc.	(1,444)				(31)
Repurchase of common stock						(1,763)
Net income attributable to noncontrolling interests	(3,457)						3,457
Foreign currency translation	(3,612)						(1,413)
Balance at end of period at Sep. 28, 2019		802	276,198	880,537	(79,823)	(470,066)	16,948
Balance at beginning of period at Jun. 29, 2019		802	280,626	857,121	(74,754)	(475,524)	16,091
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under incentive stock option plans			(341)			(601)
Stock-based compensation expense			2,053
Issuance of restricted stock			(6,140)			6,059
Net income attributable to Mueller Industries, Inc.	29,093			29,093
Dividends paid or payable to stockholders of Mueller Industries, Inc.				(5,677)
Total other comprehensive income (loss) attributable to Mueller Industries, Inc.	(5,563)				(5,069)
Repurchase of common stock						0
Net income attributable to noncontrolling interests	(1,351)						1,351
Foreign currency translation	(6,692)						(494)
Balance at end of period at Sep. 28, 2019		802	276,198	880,537	(79,823)	(470,066)	16,948
Balance at beginning of period at Dec. 28, 2019	662,136	802	278,609	903,070	(68,770)	(470,243)	18,668
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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 income (loss) attributable to Mueller Industries, Inc.	(12,601)				(12,341)
Repurchase of common stock						(5,574)
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	739,351	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]
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 income (loss) attributable to Mueller Industries, Inc.	9,640				8,688
Repurchase of common stock						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	$ 739,351	$ 802	$ 277,663	$ 988,983	$ (81,111)	$ (468,716)	$ 21,730

Recent Accounting Standards

Recent Accounting Standards	9 Months Ended
	Sep. 26, 2020
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Standards	Recent Accounting Standards Adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Disclosure Framework- Measurement of Credit Losses on Financial Instruments . The ASU significantly changes the current incurred credit loss model under U.S. GAAP, which delays the recognition of credit losses until it is probable a loss has been incurred, to a current expected credit losses model which requires immediate recognition of management estimates of credit losses. The Company adopted the ASU during the first quarter of 2020 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In August 2018, the FASB issued ASU No. 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans . For employers that sponsor defined benefit pension and/or other postretirement benefit plans, the ASU eliminates requirements for certain disclosures that are no longer considered cost beneficial, requires new disclosures related to the weighted-average interest crediting rate for cash balance plans and explanations for significant gains and losses related to changes in benefit obligations, and clarifies the requirements for entities that provide aggregate disclosures for two or more plans. The Company adopted the ASU during the first quarter of 2020 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement . The ASU eliminates requirements to disclose the amount and reasons for transfers between level 1 and level 2 of the fair value hierarchy, but requires public companies to disclose changes in unrealized gains and losses for the period included in other comprehensive income (OCI) for recurring level 3 fair value measurements or instruments held at the end of the reporting period and the range and weighted average used to develop significant unobservable inputs for level 3 fair value measurements. The Company adopted the ASU during the first quarter of 2020. The guidance on changes in unrealized gains and losses for the period included in OCI for recurring level 3 measurements, the range and weighted average of significant unobservable inputs used to develop level 3 fair value measurements, and the narrative description of measurement uncertainty is applied prospectively. All other amendments are applied retrospectively. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements.

Earnings per Common Share

Earnings per Common Share	9 Months Ended
	Sep. 26, 2020
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 three thousand and 110 thousand stock-based awards were excluded from the computation of diluted earnings per share for the quarters ended September 26, 2020 and September 28, 2019, respectively, because they were antidilutive.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 26, 2020
Business Combinations [Abstract]
Acquisitions	Acquisitions 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 provisional fair value of tangible assets acquired totaled $26.0 million, consisting primarily of inventory. Of the remaining purchase price, $31.2 million was allocated to tax-deductible goodwill and intangible assets. The purchase price allocation is provisional as of September 26, 2020 and subject to change upon completion of the final valuation of the long-lived assets during the measurement period. 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 $15.4 million, net of working capital adjustments. The total purchase price consisted of $15.4 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, $9.4 million was allocated to tax-deductible goodwill and intangible assets. The purchase price allocation is provisional as of September 26, 2020 and subject to change upon completion of the final valuation of the long-lived assets and working capital during the measurement period.

Segment Information

Segment Information	9 Months Ended
	Sep. 26, 2020
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, Die-Mold, European Operations, Trading Group, an d Jungwoo-Mueller (the Company’s South Korean joint venture). The Domestic Piping Systems Group manufactures 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. 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. European Operations manufacture 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, Fabricated Tube Products, Westermeyer, Turbotec, ATCO, Linesets, Inc., and STI. These domestic businesses manufacture and fabricate valves, assemblies, high pressure components, coaxial heat exchangers, insulated HVAC flexible duct systems, line sets, brazed manifolds, headers, and distributor assemblies 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 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 For the Quarter Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 390,917 $ 135,443 $ 90,938 $ (8,696) $ 608,602 Cost of goods sold 330,418 117,893 70,523 (8,046) 510,788 Depreciation and amortization 5,751 1,836 2,491 745 10,823 Selling, general, and administrative expense 18,738 3,115 9,961 8,925 40,739 Operating income 36,010 12,599 7,963 (10,320) 46,252 Interest expense (6,148) Other income, net 533 Income before income taxes $ 40,637 Segment information (continued): 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 54,963 8,690 19,607 31,454 114,714 Asset impairments 3,035 — — — 3,035 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 For the Nine Months Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,193,274 $ 434,037 $ 276,853 $ (17,387) $ 1,886,777 Cost of goods sold 1,019,546 372,542 212,201 (18,160) 1,586,129 Depreciation and amortization 16,953 5,518 6,932 2,453 31,856 Selling, general, and administrative expense 56,620 9,280 24,336 31,602 121,838 Operating income 100,155 46,697 33,384 (33,282) 146,954 Interest expense (20,135) Other income, net 823 Income before income taxes $ 127,642 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 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 Other — 18,129 61,647 79,776 409,414 118,831 97,604 625,849 Intersegment sales (6,744) Net sales $ 619,105 For the Quarter Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 320,789 $ — $ — $ 320,789 Brass rod and forgings — 103,616 — 103,616 OEM components, tube & assemblies 7,059 11,724 32,334 51,117 Valves and plumbing specialties 63,069 — — 63,069 Other — 20,103 58,604 78,707 390,917 135,443 90,938 617,298 Intersegment sales (8,696) Net sales $ 608,602 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 Other — 52,481 171,522 224,003 1,128,467 338,652 276,983 1,744,102 Intersegment sales (21,910) Net sales $ 1,722,192 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 986,783 $ — $ — $ 986,783 Brass rod and forgings — 333,622 — 333,622 OEM components, tube & assemblies 21,786 37,613 106,542 165,941 Valves and plumbing specialties 184,705 — — 184,705 Other — 62,802 170,311 233,113 1,193,274 434,037 276,853 1,904,164 Intersegment sales (17,387) Net sales $ 1,886,777

Cash, Cash Equivalents, and Res

Cash, Cash Equivalents, and Restricted Cash	9 Months Ended
	Sep. 26, 2020
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash (In thousands) September 26, December 28, Cash & cash equivalents $ 113,640 $ 97,944 Restricted cash included within other current assets 636 — Restricted cash included within other assets 103 98 Total cash, cash equivalents, and restricted cash $ 114,379 $ 98,042 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. 26, 2020
Inventory Disclosure [Abstract]
Inventories	Inventories (In thousands) September 26, December 28, Raw materials and supplies $ 78,210 $ 85,769 Work-in-process 41,136 48,814 Finished goods 159,674 163,842 Valuation reserves (7,710) (6,318) Inventories $ 271,310 $ 292,107

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 26, 2020
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 26, 2020, the Company held open futures contracts to purchase approximately $7.0 million of copper over the next 15 months related to fixed price sales orders. The fair value of those futures contracts was a $0.7 million 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 26, 2020, this amount was approximately $0.5 million 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 26, 2020, the Company held open futures contracts to sell approximately $0.6 million of copper over the next six months related to copper inventory. The fair value of those futures contracts was a $35 thousand net gain 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 26, December 28, Balance Sheet Location September 26, December 28, Commodity contracts - gains Other current assets $ 791 $ 1,435 Other current liabilities $ — $ 50 Commodity contracts - losses Other current assets (18) (12) Other current liabilities — (159) Total derivatives (1) $ 773 $ 1,423 $ — $ (109) (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 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Undesignated derivatives: Gain (loss) on commodity contracts (nonqualifying) Cost of goods sold 843 (467) (3,596) 1,425 The following tables summarize amounts recognized in and reclassified from AOCI during the period: 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 Quarter Ended September 28, 2019 (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 $ 130 Cost of goods sold $ (332) Other 8 Other (1) Total $ 138 Total $ (333) Changes recognized in and reclassified from AOCI (continued): 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 For the Nine Months Ended September 28, 2019 (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 $ 749 Cost of goods sold $ (629) Other 14 Other (1) Total $ 763 Total $ (630) 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 26, 2020 and December 28, 2019, the amount of restricted cash recorded in other current assets as collateral related to open derivative contracts under the master netting arrangements was immaterial. Long-Term Debt

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	9 Months Ended
	Sep. 26, 2020
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Affiliates	Investments in Unconsolidated Affiliates 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 26, December 28, Current assets $ 177,121 $ 198,559 Noncurrent assets 79,310 87,218 Current liabilities 151,298 147,801 Noncurrent liabilities 50,783 51,219 For the Quarter Ended For the Nine Months Ended (In thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net sales $ 73,850 $ 129,589 $ 284,398 $ 362,978 Gross profit 7,565 17,006 32,073 40,339 Net loss (10,916) (3,952) (40,883) (43,671) 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. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter and nine months ended September 28, 2019 included net losses of $1.9 million and $21.8 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. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the nine months ended September 26, 2020 included net income of $0.2 million for Mueller Middle East. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter and nine months ended September 28, 2019 included net losses of $0.5 million and $1.9 million, respectively, for Mueller Middle East.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 26, 2020
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 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Pension benefits: Interest cost $ 862 $ 1,455 $ 2,586 $ 4,365 Expected return on plan assets (1,496) (2,077) (4,486) (6,230) Amortization of net loss 494 485 1,482 1,455 Net periodic benefit income $ (140) $ (137) $ (418) $ (410) Other benefits: Service cost $ 59 $ 64 $ 176 $ 191 Interest cost 106 153 321 459 Amortization of prior service credit (117) (226) (401) (677) Amortization of net gain (50) (10) (150) (31) Curtailment gain — $ — (2,591) $ — Net periodic benefit income $ (2) $ (19) $ (2,645) $ (58) 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. 26, 2020
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 $12.7 million and $17.7 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 $1.8 million and $2.3 million over the next 17 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 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, $0.4 million of which has been incurred by those PRPs and paid for by the Company to date. As of September 26, 2020, the Company has made payments of approximately $7.1 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. In October 2017, a group of private plaintiffs sued the Company, Arava, MRRC, and Lead Refinery, along with other defendants, in a private tort action relating to the site; the Company, Arava, and MRRC were voluntarily dismissed from that litigation without prejudice in March 2018. A second civil action asserting similar claims was filed against the Company, Arava, MRRC, and Lead Refinery in September 2018. 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 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 $0.6 million to $0.9 million over the next six years. 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. Equal Employment Opportunity Commission Matter On October 5, 2016, the Company received a demand letter from the Los Angeles District Office of the United States Equal Employment Opportunity Commission (EEOC). The EEOC alleged that between May 2011 and April 2015, various Company employees were terminated in violation of the Americans with Disabilities Act (ADA), and that certain of the Company’s employee leave and attendance policies were discriminatory in nature. Thereafter, the Company, in consultation with its liability insurers, entered into conciliation and mediation efforts with the EEOC for purposes of resolving the claims. At the conclusion of those efforts, the Company and the EEOC reached agreement on a consensual resolution of the EEOC’s claims, which includes both monetary and equitable relief. On June 28, 2018, the EEOC filed a complaint against the Company on behalf of a group of unidentified claimants in the United States District Court for the Central District of California alleging that the Company engaged in unlawful employment practices in violation of the ADA. On July 13, 2018, the District Court approved a Consent Decree between the Company and the EEOC to resolve the EEOC’s claims. The Consent Decree, the term of which shall be two and a half years, provides that the Company shall pay up to $1.0 million in monetary relief to fund individual claims for discrimination under the ADA as approved by the EEOC. That amount is fully within the limits of the Company’s applicable insurance coverage. Pursuant to the Consent Decree, the Company shall also take a series of proactive measures to cultivate a work environment free from unlawful discrimination. Those measures include, among others, assistance with the identification of potential claimants, employee, supervisory and managerial training regarding employee rights under the ADA, revised practices and procedures concerning reasonable workplace accommodations as required by the ADA, and related reporting and recordkeeping. Deepwater Horizon Economic and Property Damage Claim On February 12, 2020, Mueller Copper Tube Company, a wholly owned subsidiary of the Company, collected approximately $21.9 million related to its claim under the Deepwater Horizon Economic and Property Damage Settlement Program, which as previously reported by the Company, was originally approved in November 2018, subject to appeal. 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 maximum payments that the Company could be required to make under its guarantees at September 26, 2020 were $19.5 million.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 26, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the third quarter of 2020 was 24 percent compared with 19 percent for the same period last year. The primary 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 totaling $0.4 million. The Company’s effective tax rate for the third quarter of 2019 was 19 percent. The items impacting the effective tax rate for the third quarter of 2019 were primarily attributable to benefits of $1.0 million related to the one-time transition tax on the accumulated earnings of certain foreign subsidiaries and $0.8 million related to other items. These were partially offset by the provision for state income taxes, net of the federal benefit, of $1.0 million. The Company’s effective tax rate for the first nine months of 2020 was 25 percent compared with 22 percent for the same period last year. The items impacting the effective tax rate for the first nine months of 2020 were primarily attributable 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’s effective tax rate for the first nine months of 2019 was 22 percent. The items impacting the effective tax rate for the first nine months of 2019 were primarily attributable to the provision for state income taxes, net of the federal benefit, of $3.3 million, which was partially offset by the recognition of a $1.6 million benefit related to an increased tax loss on the sale of a foreign subsidiary in a prior period, a reduction of $0.6 million related to the one-time transition tax on the accumulated earnings of certain foreign subsidiaries, and $0.3 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 return and most state income tax returns for 2015 and all subsequent years, and is open for certain state and foreign returns for earlier tax years due to ongoing audits and differing statute periods. The Internal Revenue Service is currently auditing the Company’s 2015 and 2017 federal consolidated returns. While the Company believes that it is adequately reserved for possible future 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. 26, 2020
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 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 (11,254) 192 (715) (564) (12,341) Balance as of September 26, 2020 $ (57,452) $ 668 $ (22,570) $ (1,757) $ (81,111) For the Nine Months Ended September 28, 2019 (In thousands) Cumulative Translation Adjustment Unrealized (Loss) Gain on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 29, 2018 $ (54,257) $ (214) $ (24,967) $ (354) $ (79,792) Other comprehensive (loss) income before reclassifications (2,199) 763 587 828 (21) Amounts reclassified from AOCI — (630) 620 — (10) Net current-period other comprehensive (loss) income (2,199) 133 1,207 828 (31) Balance as of September 28, 2019 $ (56,456) $ (81) $ (23,760) $ 474 $ (79,823) Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI For the Quarter Ended For the Nine Months Ended (In thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Affected line item Unrealized (gains) losses on derivative commodity contracts $ (248) $ (394) $ 6,581 $ (764) Cost of goods sold 68 61 (1,307) 134 Income tax expense (benefit) $ (180) $ (333) $ 5,274 $ (630) Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 327 $ 249 $ 931 $ 747 Other income, net (63) (42) (178) (127) Income tax benefit $ 264 $ 207 $ 753 $ 620 Net of tax and noncontrolling interests

Recent Accounting Standards (Po

Recent Accounting Standards (Policies)	9 Months Ended
	Sep. 26, 2020
Accounting Changes and Error Corrections [Abstract]
Recently Adopted Accounting Standards	Adopted In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Disclosure Framework- Measurement of Credit Losses on Financial Instruments . The ASU significantly changes the current incurred credit loss model under U.S. GAAP, which delays the recognition of credit losses until it is probable a loss has been incurred, to a current expected credit losses model which requires immediate recognition of management estimates of credit losses. The Company adopted the ASU during the first quarter of 2020 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In August 2018, the FASB issued ASU No. 2018-14, Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans . For employers that sponsor defined benefit pension and/or other postretirement benefit plans, the ASU eliminates requirements for certain disclosures that are no longer considered cost beneficial, requires new disclosures related to the weighted-average interest crediting rate for cash balance plans and explanations for significant gains and losses related to changes in benefit obligations, and clarifies the requirements for entities that provide aggregate disclosures for two or more plans. The Company adopted the ASU during the first quarter of 2020 using a retrospective approach. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement . The ASU eliminates requirements to disclose the amount and reasons for transfers between level 1 and level 2 of the fair value hierarchy, but requires public companies to disclose changes in unrealized gains and losses for the period included in other comprehensive income (OCI) for recurring level 3 fair value measurements or instruments held at the end of the reporting period and the range and weighted average used to develop significant unobservable inputs for level 3 fair value measurements. The Company adopted the ASU during the first quarter of 2020. The guidance on changes in unrealized gains and losses for the period included in OCI for recurring level 3 measurements, the range and weighted average of significant unobservable inputs used to develop level 3 fair value measurements, and the narrative description of measurement uncertainty is applied prospectively. All other amendments are applied retrospectively. The adoption of the ASU did not have a material impact on the Company’s Condensed Consolidated Financial Statements.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 26, 2020
Segment Reporting [Abstract]
Summary of Segment Information	Summarized segment information is as follows: 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 For the Quarter Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 390,917 $ 135,443 $ 90,938 $ (8,696) $ 608,602 Cost of goods sold 330,418 117,893 70,523 (8,046) 510,788 Depreciation and amortization 5,751 1,836 2,491 745 10,823 Selling, general, and administrative expense 18,738 3,115 9,961 8,925 40,739 Operating income 36,010 12,599 7,963 (10,320) 46,252 Interest expense (6,148) Other income, net 533 Income before income taxes $ 40,637 Segment information (continued): 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 54,963 8,690 19,607 31,454 114,714 Asset impairments 3,035 — — — 3,035 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 For the Nine Months Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,193,274 $ 434,037 $ 276,853 $ (17,387) $ 1,886,777 Cost of goods sold 1,019,546 372,542 212,201 (18,160) 1,586,129 Depreciation and amortization 16,953 5,518 6,932 2,453 31,856 Selling, general, and administrative expense 56,620 9,280 24,336 31,602 121,838 Operating income 100,155 46,697 33,384 (33,282) 146,954 Interest expense (20,135) Other income, net 823 Income before income taxes $ 127,642
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 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 Other — 18,129 61,647 79,776 409,414 118,831 97,604 625,849 Intersegment sales (6,744) Net sales $ 619,105 For the Quarter Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 320,789 $ — $ — $ 320,789 Brass rod and forgings — 103,616 — 103,616 OEM components, tube & assemblies 7,059 11,724 32,334 51,117 Valves and plumbing specialties 63,069 — — 63,069 Other — 20,103 58,604 78,707 390,917 135,443 90,938 617,298 Intersegment sales (8,696) Net sales $ 608,602 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 Other — 52,481 171,522 224,003 1,128,467 338,652 276,983 1,744,102 Intersegment sales (21,910) Net sales $ 1,722,192 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 28, 2019 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 986,783 $ — $ — $ 986,783 Brass rod and forgings — 333,622 — 333,622 OEM components, tube & assemblies 21,786 37,613 106,542 165,941 Valves and plumbing specialties 184,705 — — 184,705 Other — 62,802 170,311 233,113 1,193,274 434,037 276,853 1,904,164 Intersegment sales (17,387) Net sales $ 1,886,777

Cash, Cash Equivalents, and R_2

Cash, Cash Equivalents, and Restricted Cash (Tables)	9 Months Ended
	Sep. 26, 2020
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	(In thousands) September 26, December 28, Cash & cash equivalents $ 113,640 $ 97,944 Restricted cash included within other current assets 636 — Restricted cash included within other assets 103 98 Total cash, cash equivalents, and restricted cash $ 114,379 $ 98,042
Restrictions on Cash and Cash Equivalents	(In thousands) September 26, December 28, Cash & cash equivalents $ 113,640 $ 97,944 Restricted cash included within other current assets 636 — Restricted cash included within other assets 103 98 Total cash, cash equivalents, and restricted cash $ 114,379 $ 98,042

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 26, 2020
Inventory Disclosure [Abstract]
Inventories	(In thousands) September 26, December 28, Raw materials and supplies $ 78,210 $ 85,769 Work-in-process 41,136 48,814 Finished goods 159,674 163,842 Valuation reserves (7,710) (6,318) Inventories $ 271,310 $ 292,107

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 26, 2020
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 26, December 28, Balance Sheet Location September 26, December 28, Commodity contracts - gains Other current assets $ 791 $ 1,435 Other current liabilities $ — $ 50 Commodity contracts - losses Other current assets (18) (12) Other current liabilities — (159) Total derivatives (1) $ 773 $ 1,423 $ — $ (109) (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 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Undesignated derivatives: Gain (loss) on commodity contracts (nonqualifying) Cost of goods sold 843 (467) (3,596) 1,425
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 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 Quarter Ended September 28, 2019 (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 $ 130 Cost of goods sold $ (332) Other 8 Other (1) Total $ 138 Total $ (333) Changes recognized in and reclassified from AOCI (continued): 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 For the Nine Months Ended September 28, 2019 (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 $ 749 Cost of goods sold $ (629) Other 14 Other (1) Total $ 763 Total $ (630)

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	9 Months Ended
	Sep. 26, 2020
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 26, December 28, Current assets $ 177,121 $ 198,559 Noncurrent assets 79,310 87,218 Current liabilities 151,298 147,801 Noncurrent liabilities 50,783 51,219 For the Quarter Ended For the Nine Months Ended (In thousands) September 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Net sales $ 73,850 $ 129,589 $ 284,398 $ 362,978 Gross profit 7,565 17,006 32,073 40,339 Net loss (10,916) (3,952) (40,883) (43,671)

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 26, 2020
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 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Pension benefits: Interest cost $ 862 $ 1,455 $ 2,586 $ 4,365 Expected return on plan assets (1,496) (2,077) (4,486) (6,230) Amortization of net loss 494 485 1,482 1,455 Net periodic benefit income $ (140) $ (137) $ (418) $ (410) Other benefits: Service cost $ 59 $ 64 $ 176 $ 191 Interest cost 106 153 321 459 Amortization of prior service credit (117) (226) (401) (677) Amortization of net gain (50) (10) (150) (31) Curtailment gain — $ — (2,591) $ — Net periodic benefit income $ (2) $ (19) $ (2,645) $ (58)

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 26, 2020
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 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 (11,254) 192 (715) (564) (12,341) Balance as of September 26, 2020 $ (57,452) $ 668 $ (22,570) $ (1,757) $ (81,111) For the Nine Months Ended September 28, 2019 (In thousands) Cumulative Translation Adjustment Unrealized (Loss) Gain on Derivatives Pension/OPEB Liability Adjustment Attributable to Unconsol. Affiliates Total Balance as of December 29, 2018 $ (54,257) $ (214) $ (24,967) $ (354) $ (79,792) Other comprehensive (loss) income before reclassifications (2,199) 763 587 828 (21) Amounts reclassified from AOCI — (630) 620 — (10) Net current-period other comprehensive (loss) income (2,199) 133 1,207 828 (31) Balance as of September 28, 2019 $ (56,456) $ (81) $ (23,760) $ 474 $ (79,823)
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 26, 2020 September 28, 2019 September 26, 2020 September 28, 2019 Affected line item Unrealized (gains) losses on derivative commodity contracts $ (248) $ (394) $ 6,581 $ (764) Cost of goods sold 68 61 (1,307) 134 Income tax expense (benefit) $ (180) $ (333) $ 5,274 $ (630) Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 327 $ 249 $ 931 $ 747 Other income, net (63) (42) (178) (127) Income tax benefit $ 264 $ 207 $ 753 $ 620 Net of tax and noncontrolling interests

Earnings per Common Share Earni

Earnings per Common Share Earnings per Common Share (Details) - shares shares in Thousands	3 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Earnings Per Share [Abstract]
Stock-based awards excluded from computation of diluted earnings per share (in shares)	3	110

Acquisitions - Narrative (Detai

Acquisitions - Narrative (Details) - USD ($) $ in Millions	Aug. 03, 2020	Jan. 17, 2020
Wieland-Kessler LLC Asset Acquisition [Member]
Business Acquisition [Line Items]
Payments for asset acquisition	$ 57.2
Asset acquisition, fair value of assets acquired	26
Asset acquisition, goodwill and intangible assets	$ 31.2
Shoals Tubular, Inc. [Member]
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments		$ 15.4
Cash portion of acquisition price		15.4
Fair value of assets acquired		6.2
Fair value of property, plant and equipment acquired		3.7
Fair value of inventories acquired		1.8
Fair value of accounts receivable acquired		0.7
Fair value of liabilities acquired		0.2
Tax-deductible goodwill		$ 9.4

Segment Information - Summary o

Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Summary of segment information [Abstract]
Net sales	$ 619,105	$ 608,602	$ 1,722,192	$ 1,886,777
Cost of goods sold	500,780	510,788	1,412,654	1,586,129
Depreciation and amortization	10,752	10,823	32,888	31,856
Selling, general, and administrative expense	38,346	40,739	114,714	121,838
Asset impairments	0	0	3,035	0
Litigation settlement, net	0	0	(21,933)	0
Operating income	69,227	46,252	180,834	146,954
Interest expense	(4,885)	(6,148)	(15,237)	(20,135)
Other income (expense), net	522	533	3,634	823
Income before income taxes	64,864	40,637	169,231	127,642
Operating Segments [Member]
Summary of segment information [Abstract]
Net sales	625,849	617,298	1,744,102	1,904,164
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	409,414	390,917	1,128,467	1,193,274
Cost of goods sold	339,904	330,418	931,339	1,019,546
Depreciation and amortization	5,362	5,751	16,517	16,953
Selling, general, and administrative expense	19,285	18,738	54,963	56,620
Asset impairments			3,035
Litigation settlement, net			0
Operating income	44,863	36,010	122,613	100,155
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	118,831	135,443	338,652	434,037
Cost of goods sold	95,717	117,893	285,788	372,542
Depreciation and amortization	1,774	1,836	5,771	5,518
Selling, general, and administrative expense	2,992	3,115	8,690	9,280
Asset impairments			0
Litigation settlement, net			0
Operating income	18,348	12,599	38,403	46,697
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	97,604	90,938	276,983	276,853
Cost of goods sold	70,450	70,523	206,083	212,201
Depreciation and amortization	2,547	2,491	7,770	6,932
Selling, general, and administrative expense	6,451	9,961	19,607	24,336
Asset impairments			0
Litigation settlement, net			0
Operating income	18,156	7,963	43,523	33,384
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(6,744)	(8,696)	(21,910)	(17,387)
Cost of goods sold	(5,291)	(8,046)	(10,556)	(18,160)
Depreciation and amortization	1,069	745	2,830	2,453
Selling, general, and administrative expense	9,618	8,925	31,454	31,602
Asset impairments			0
Litigation settlement, net			(21,933)
Operating income	$ (12,140)	$ (10,320)	$ (23,705)	$ (33,282)

Segment Information - Net Sales

Segment Information - Net Sales by Major Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 619,105	$ 608,602	$ 1,722,192	$ 1,886,777
Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	625,849	617,298	1,744,102	1,904,164
Operating Segments [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	409,414	390,917	1,128,467	1,193,274
Operating Segments [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	118,831	135,443	338,652	434,037
Operating Segments [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	97,604	90,938	276,983	276,853
Operating Segments [Member] | Tube and fittings [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	320,619	320,789	878,764	986,783
Operating Segments [Member] | Tube and fittings [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	320,619	320,789	878,764	986,783
Operating Segments [Member] | Tube and fittings [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Tube and fittings [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Brass rod and forgings [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	89,487	103,616	253,647	333,622
Operating Segments [Member] | Brass rod and forgings [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Brass rod and forgings [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	89,487	103,616	253,647	333,622
Operating Segments [Member] | Brass rod and forgings [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | OEM components, tube and assemblies [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	54,574	51,117	187,494	165,941
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	7,402	7,059	49,509	21,786
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	11,215	11,724	32,524	37,613
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	35,957	32,334	105,461	106,542
Operating Segments [Member] | Valves and plumbing specialties [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	81,393	63,069	200,194	184,705
Operating Segments [Member] | Valves and plumbing specialties [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	81,393	63,069	200,194	184,705
Operating Segments [Member] | Valves and plumbing specialties [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Valves and plumbing specialties [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	79,776	78,707	224,003	233,113
Operating Segments [Member] | Other [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0	0	0
Operating Segments [Member] | Other [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	18,129	20,103	52,481	62,802
Operating Segments [Member] | Other [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	61,647	58,604	171,522	170,311
Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ (6,744)	$ (8,696)	$ (21,910)	$ (17,387)

Cash, Cash Equivalents, and R_3

Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019	Sep. 28, 2019	Dec. 29, 2018
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 113,640	$ 97,944
Restricted cash included within other current assets	636	0
Restricted cash included within other assets	103	98
Total cash, cash equivalents, and restricted cash	$ 114,379	$ 98,042	$ 102,503	$ 77,138

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 78,210	$ 85,769
Work-in-process	41,136	48,814
Finished goods	159,674	163,842
Valuation reserves	(7,710)	(6,318)
Inventories	$ 271,310	$ 292,107

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) - Commodity Contracts [Member] $ in Thousands	9 Months Ended
	Sep. 26, 2020USD ($)
Derivative [Line Items]
Deferred net gains (losses), net of tax, included in AOCI	$ 500
Cash Flow Hedging [Member] | Long [Member]
Derivative [Line Items]
Open option contracts written, at fair value	$ 7,000
Time period for open copper future contract purchases	15 months
Fair value of future contracts with net gain (loss) position	$ 700
Fair Value Hedging [Member] | Short [Member]
Derivative [Line Items]
Fair value of future contracts with net gain (loss) position	35
Open future contracts to sell copper	$ 600
Time period for open copper future contract sales	6 months

Financial Instruments - Summary

Financial Instruments - Summary of Location and Fair Value (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 28, 2019
Derivatives, Fair Value [Line Items]
Total derivative assets	$ 773	$ 1,423
Total derivative liabilities	0	(109)
Other Current Assets [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	791	1,435
Other current assets: Loss positions	(18)	(12)
Other Current Liabilities [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Other current liability: Gain positions	0	50
Other current liability: Loss positions	$ 0	$ (159)

Financial Instruments - Effects

Financial Instruments - Effects of Derivative Instruments on Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Commodity Contracts [Member] | Cost of Goods Sold [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on commodity contracts (nonqualifying)	$ 843	$ (467)	$ (3,596)	$ 1,425

Financial Instruments - Amounts

Financial Instruments - Amounts Recognized in and Reclassified from AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	$ 151	$ (195)	$ 192	$ 133
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	331	138	(5,082)	763
Gain Reclassified from AOCI (Effective Portion), Net of Tax	(180)	(333)	5,274	(630)
Commodity Contracts [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	337	130	(5,084)	749
Commodity Contracts [Member] | Cash Flow Hedging [Member] | Cost of Goods Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain Reclassified from AOCI (Effective Portion), Net of Tax	(180)	(332)	5,273	(629)
Other [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI (Effective Portion), Net of Tax	(6)	8	2	14
Gain Reclassified from AOCI (Effective Portion), Net of Tax	$ 0	$ (1)	$ 1	$ (1)

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		57 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020
Schedule of Equity Method Investments [Line Items]
Net loss	$ 43,957	$ 30,444	$ 106,395	$ 76,259
Tecumseh Products Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50.00%		50.00%		50.00%
Net loss	$ (5,500)	(1,900)	$ (20,400)	(21,800)
Second Unconsolidated Affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50.00%		50.00%		50.00%
Mueller Middle East [Member]
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	40.00%		40.00%		40.00%
Net loss		$ (500)	$ 200	$ (1,900)
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. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Balance sheet data [Abstract]
Current assets	$ 729,865		$ 729,865		$ 693,772
Current liabilities	252,752		252,752		234,287
Income Statement [Abstract]
Net sales	619,105	$ 608,602	1,722,192	$ 1,886,777
Net loss	43,957	30,444	106,395	76,259
Tecumseh
Balance sheet data [Abstract]
Current assets	177,121		177,121		198,559
Noncurrent assets	79,310		79,310		87,218
Current liabilities	151,298		151,298		147,801
Noncurrent liabilities	50,783		50,783		$ 51,219
Income Statement [Abstract]
Net sales	73,850	129,589	284,398	362,978
Gross profit	7,565	17,006	32,073	40,339
Net loss	$ (10,916)	$ (3,952)	$ (40,883)	$ (43,671)

Benefit Plans (Details)

Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Pension Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Interest cost	$ 862	$ 1,455	$ 2,586	$ 4,365
Expected return on plan assets	(1,496)	(2,077)	(4,486)	(6,230)
Amortization of net loss (gain)	494	485	1,482	1,455
Net periodic benefit income	(140)	(137)	(418)	(410)
Other Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	59	64	176	191
Interest cost	106	153	321	459
Amortization of prior service credit	(117)	(226)	(401)	(677)
Amortization of net loss (gain)	(50)	(10)	(150)	(31)
Curtailment gain	0	0	(2,591)	0
Net periodic benefit income	$ (2)	$ (19)	$ (2,645)	$ (58)

Commitments and Contingencies (

Commitments and Contingencies (Details)	Jul. 13, 2018USD ($)	Jan. 31, 2018USD ($)unilateral_administrative_orderpotentially_responsible_party	Nov. 27, 2015USD ($)	Sep. 26, 2020USD ($)propertysmelter_site	Oct. 31, 2008Import_entry	Sep. 26, 2020USD ($)smelter_site	Sep. 26, 2020potentially_responsible_party	Sep. 26, 2020USD ($)	Feb. 12, 2020USD ($)	Nov. 08, 2016USD ($)	Apr. 19, 2010
Loss Contingencies [Line Items]
Term of guarantees				1 year
Payments required to be made under guarantees, maximum								$ 19,500,000
United States Department of Commerce Antidumping Review [Member]
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			$ 3,000,000
Number of import entries | Import_entry					795
Unlawful Employment Practices [Member]
Loss Contingencies [Line Items]
Term of consent decree	2 years 6 months
Maximum amount to be paid to fund discrimination claims	$ 1,000,000
Deepwater Horizon Economic and Property Damage Claim [Member]
Loss Contingencies [Line Items]
Amount awarded to the Company									$ 21,900,000
Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Financial guarantee										$ 1,000,000
Lead Refinery NPL Site [Member]
Loss Contingencies [Line Items]
Environmental reserves		$ 4,500,000
Number of UAOs | unilateral_administrative_order		2
Number of PRPs | potentially_responsible_party		4
Site contingency, total costs		$ 25,000,000
Site contingency, amount agreed upon to pay PRPs for past costs		2,000,000
Site contingency, additional reimbursement of past costs		$ 700,000
Site contingency, amount paid to date for reimbursement of costs						$ 400,000
Contingency charge				$ 7,100,000
Non operating Properties [Member] | Southeast Kansas Sites [Member]
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations				3		3	2
Environmental reserves								$ 5,600,000
Non operating Properties [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Period of permit, implementation of Best Management Practices				10 years
Estimated remediation costs, term				30 years
Non operating Properties [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations | potentially_responsible_party							2
Estimated remediation costs, term				17 years
Amount other PRPs will pay to fund cleanup				$ 26,000,000
Number of surrounding properties | property				300
Non operating Properties [Member] | Minimum [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 12,700,000
Non operating Properties [Member] | Minimum [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				1,800,000
Non operating Properties [Member] | Maximum [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				17,700,000
Non operating Properties [Member] | Maximum [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 2,300,000
Operating Properties [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs, term				6 years
Operating Properties [Member] | Minimum [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 600,000
Operating Properties [Member] | Maximum [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 900,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	24.00%	19.00%	25.00%	22.00%
Provision for state income taxes, net of federal benefits	$ 1.4	$ 1	$ 4.8	$ 3.3
Other items	$ 0.4	0.8	0.6	0.3
Tax Act, increase in transition tax		$ 1		0.6
Effect of foreign tax rates differential			$ 1.7
Impact of investments in foreign subsidiary				$ 1.6

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. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			$ 662,136
Total other comprehensive income (loss), net	$ 9,640	$ (5,563)	(12,601)	$ (1,444)
Balance at end of period	739,351		739,351
Cumulative Translation Adjustment [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(46,198)	(54,257)
Other comprehensive loss before reclassifications			(11,254)	(2,199)
Amounts reclassified from AOCI			0	0
Total other comprehensive income (loss), net			(11,254)	(2,199)
Balance at end of period	(57,452)	(56,456)	(57,452)	(56,456)
Unrealized (Loss) Gain on Derivatives [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			476	(214)
Other comprehensive loss before reclassifications			(5,082)	763
Amounts reclassified from AOCI			5,274	(630)
Total other comprehensive income (loss), net			192	133
Balance at end of period	668	(81)	668	(81)
Pension/OPEB Liability Adjustment [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(21,855)	(24,967)
Other comprehensive loss before reclassifications			(1,468)	587
Amounts reclassified from AOCI			753	620
Total other comprehensive income (loss), net			(715)	1,207
Balance at end of period	(22,570)	(23,760)	(22,570)	(23,760)
Attributable to Unconsolidated Affiliates [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period			(1,193)	(354)
Other comprehensive loss before reclassifications			(564)	828
Amounts reclassified from AOCI			0	0
Total other comprehensive income (loss), net			(564)	828
Balance at end of period	(1,757)	474	(1,757)	474
Total [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Balance at beginning of period	(89,799)	(74,754)	(68,770)	(79,792)
Other comprehensive loss before reclassifications			(18,368)	(21)
Amounts reclassified from AOCI			6,027	(10)
Total other comprehensive income (loss), net	8,688	(5,069)	(12,341)	(31)
Balance at end of period	$ (81,111)	$ (79,823)	$ (81,111)	$ (79,823)

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. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 500,780	$ 510,788	$ 1,412,654	$ 1,586,129
Income tax (benefit) expense	15,450	7,665	42,623	27,643
Net of tax and noncontrolling interests	(42,702)	(29,093)	(103,073)	(72,802)
Other income, net	(522)	(533)	(3,634)	(823)
Unrealized (gains) losses on derivative commodity contracts [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	(248)	(394)	6,581	(764)
Income tax (benefit) expense	68	61	(1,307)	134
Net of tax and noncontrolling interests	(180)	(333)	5,274	(630)
Amortization of net loss and prior service cost on employee benefit plans [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (benefit) expense	(63)	(42)	(178)	(127)
Net of tax and noncontrolling interests	264	207	753	620
Other income, net	$ 327	$ 249	$ 931	$ 747