Mueller Industries (MLI) 10-Q 24 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 29, 2018	Oct. 19, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	MUELLER INDUSTRIES INC
Entity Central Index Key	89,439
Current Fiscal Year End Date	--12-29
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 29, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		57,669,954

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	[1]	Sep. 29, 2018	Sep. 30, 2017	[1]
Income Statement [Abstract]
Net sales	$ 645,958	$ 550,363		$ 1,948,791	$ 1,742,549
Cost of goods sold	566,956	471,262		1,676,446	1,484,000
Depreciation and amortization	10,619	8,266		29,081	25,216
Selling, general, and administrative expense	38,889	33,214		112,077	104,676
Asset impairments	0	0		0	411	[2]
(Gain) loss on sale of assets	(2,691)	140		(334)	(1,491)
Insurance recovery	(1,486)	0		(1,486)	0	[2]
Operating income	33,671	37,481		133,007	129,737
Interest expense	(6,746)	(5,237)		(18,728)	(14,210)
Other income (expense), net	411	(380)		1,557	556
Income before income taxes	27,336	31,864		115,836	116,083
Income tax expense	(3,373)	(8,716)		(23,179)	(33,295)
Loss from unconsolidated affiliates, net of foreign tax	(3,100)	(394)		(13,568)	(1,746)	[2]
Consolidated net income	20,863	22,754		79,089	81,042	[2]
Net income attributable to noncontrolling interests	(571)	(496)		(1,487)	(1,164)
Net income attributable to Mueller Industries, Inc.	$ 20,292	$ 22,258		$ 77,602	$ 79,878
Weighted average shares for basic earnings per share (in shares)	56,877	56,987		56,858	56,891
Effect of dilutive stock-based awards (in shares)	540	456		524	542
Adjusted weighted average shares for diluted earnings per share (in shares)	57,417	57,443		57,382	57,433
Basic earnings per share (in dollars per share)	$ 0.36	$ 0.39		$ 1.36	$ 1.40
Diluted earnings per share (in dollars per share)	0.35	0.39		1.35	1.39
Dividends per share (in dollars per share)	$ 0.1	$ 0.1		$ 0.3	$ 8.3
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.
[2]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017		Sep. 29, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Consolidated net income	$ 20,863	$ 22,754	[1]	$ 79,089	$ 81,042	[1],[2]
Other comprehensive income (loss), net of tax:
Foreign currency translation	1,111	7,154		(5,534)	15,270
Net change with respect to derivative instruments and hedging activities, net of tax of $(33), $23, $243, and $(162)	131	(132)		(896)	185
Net change in pension and postretirement obligation adjustments, net of tax of $(79), $102, $(221), and $285	270	(207)		769	(572)
Attributable to unconsolidated affiliates, net of tax of $2,005, $415, $2,086, and $614	(6,907)	(735)		(7,187)	(1,086)
Other, net	0	0		0	(380)
Total other comprehensive (loss) income, net	(5,395)	6,080		(12,848)	13,417
Consolidated comprehensive income	15,468	28,834		66,241	94,459
Comprehensive income attributable to noncontrolling interests	(34)	(499)		(1,097)	(2,002)
Comprehensive income attributable to Mueller Industries, Inc.	$ 15,434	$ 28,335		$ 65,144	$ 92,457
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.
[2]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net change with respect to derivative instruments and hedging activities, tax (expense) benefit	$ (33)	$ 23	$ 243	$ (162)
Net actuarial loss on pension and postretirement obligations, tax benefit (expense)	(79)	102	(221)	285
Attributable to unconsolidated affiliates, tax benefit (expense)	$ 2,005	$ 415	$ 2,086	$ 614

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Current assets:
Cash and cash equivalents	$ 104,735	$ 120,269
Accounts receivable, less allowance for doubtful accounts of $795 in 2018 and $980 in 2017	308,231	244,795
Inventories	313,396	327,901
Other current assets	34,842	46,150
Total current assets	761,204	739,115
Property, plant, and equipment, net	360,655	304,321
Goodwill, net	150,407	130,293
Intangible assets, net	64,786	42,008
Investments in unconsolidated affiliates	58,054	80,286
Other assets	26,637	24,150
Total assets	1,421,743	1,320,173
Current liabilities:
Current portion of debt	9,254	16,480
Accounts payable	121,412	102,503
Accrued wages and other employee costs	37,703	33,546
Other current liabilities	75,914	89,723
Total current liabilities	244,283	242,252
Long-term debt, less current portion	510,032	448,592
Pension liabilities	9,941	11,606
Postretirement benefits other than pensions	16,903	17,107
Environmental reserves	21,339	23,699
Deferred income taxes	17,299	19,403
Other noncurrent liabilities	18,538	21,486
Total liabilities	838,335	784,145
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 57,840,053 in 2018 and 57,809,509 in 2017	802	802
Additional paid-in capital	274,767	274,585
Retained earnings	803,627	743,503
Accumulated other comprehensive loss	(62,957)	(51,056)
Treasury common stock, at cost	(447,253)	(445,723)
Total Mueller Industries, Inc. stockholders' equity	568,986	522,111
Noncontrolling interests	14,422	13,917
Total equity	583,408	536,028
Commitments and contingencies	0	0
Total liabilities and equity	$ 1,421,743	$ 1,320,173

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 795	$ 980
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)	57,840,053	57,809,509

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	[1]
Cash flows from operating activities
Consolidated net income	$ 79,089	$ 81,042	[2]
Reconciliation of consolidated net income to net cash provided by operating activities:
Depreciation and amortization	29,320	25,439
Stock-based compensation expense	5,953	5,555
Loss from unconsolidated affiliates	13,568	1,746	[2]
Gain on sale of business	0	(1,491)
Gain on disposals of properties	(247)	(26)
Gain on sales of securities	0	(611)
Impairment charge	0	411	[2]
Insurance recovery	(1,486)	0	[2]
Deferred income taxes	(1,502)	624
Changes in assets and liabilities, net of effects of businesses acquired and sold:
Receivables	(42,201)	(33,359)
Inventories	48,716	(40,920)
Other assets	11,250	(3,372)
Current liabilities	(7,947)	20,967
Other liabilities	(13,862)	(1,498)
Other, net	1,864	(965)
Net cash provided by operating activities	122,515	53,542
Cash flows from investing activities
Capital expenditures	(16,685)	(17,297)
Acquisition of businesses, net of cash acquired	(167,677)	(18,396)
Proceeds from sale of business, net of cash sold	0	17,483
Investments in unconsolidated affiliates	(609)	(3,317)
Proceeds from sales of assets	18,693	11,732
Proceeds from sales of securities	0	1,787
Net cash used in investing activities	(166,278)	(8,008)
Cash flows from financing activities
Dividends paid to stockholders of Mueller Industries, Inc.	(17,051)	(191,241)
Dividends paid to noncontrolling interests	(592)	(2,909)
Repurchase of common stock	(6,575)	0
Issuance of long-term debt	194,131	0
Repayments of long-term debt	(139,518)	(100,917)
Repayment of debt by consolidated joint ventures, net	(2,978)	(3,451)
Net cash used to settle stock-based awards	(726)	(1,644)
Net cash provided by (used in) financing activities	26,691	(300,162)
Effect of exchange rate changes on cash	(442)	4,466
Decrease in cash, cash equivalents, and restricted cash	(17,514)	(250,162)
Cash, cash equivalents, and restricted cash at the beginning of the period	126,563	360,469
Cash, cash equivalents, and restricted cash at the end of the period	$ 109,049	$ 110,307
[1]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.
[2]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.

Recent Accounting Standards

Recent Accounting Standards	9 Months Ended
	Sep. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Standards	Recent Accounting Standards Adopted In February 2018, the Financial Accounting Standards Board (FASB) issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (AOCI) . The ASU permits entities to reclassify tax effects stranded in AOCI as a result of tax reform to retained earnings. The guidance is effective for the Company in interim and annual periods beginning in 2019. Early adoption is permitted and can be applied retrospectively or in the period of adoption. The Company early adopted the ASU during the first quarter of 2018, which resulted in a net reclassification of $556 thousand from AOCI to retained earnings during the quarter. In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . The ASU requires employers that sponsor defined benefit pension and/or other postretirement benefit plans to present the service cost component of net periodic benefit cost in the same income statement line item(s) as other employee compensation costs arising from services rendered during the period and other components of net periodic benefits cost separately from the line item(s) that includes the service cost and outside of any subtotal of operating income. The Company adopted the ASU during the first quarter of 2018 using a retrospective approach for each period presented, and elected to use the practical expedient that allows the Company to use the amounts previously presented in its Benefit Plans disclosure as the estimation basis for applying the retrospective presentation requirements. Prior to the adoption of the ASU, net periodic benefit cost (income) was reported within selling, general, and administrative expense in the Condensed Consolidated Statements of Income. The prior periods have been revised to conform to the current period presentation, resulting in the reclassification of $78 thousand and $232 thousand of net periodic benefit income from operating income to other income (expense), net for the quarter and nine months ended September 30, 2017 , respectively. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business . The ASU provides guidance to assist entities in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The updated guidance requires prospective adoption. Early adoption is permitted. The Company early adopted the ASU during the first quarter of 2018 and the adoption had no impact on its Condensed Consolidated Financial Statements. In December 2016, the FASB issued ASU No. 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . The ASU provides correction or improvement to the guidance previously issued in Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers . Under the ASU, an entity will recognize revenue to depict the transfer of promised goods or services to customers at an amount that reflects the consideration that it expects to receive in exchange for the goods or services. It also requires more detailed disclosures to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The ASU requires revenue to be recognized over time (i.e., throughout the production process) rather than at a point in time (generally upon shipment to the customer) if performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date. The Company generates revenue through the manufacture and sale of copper tube and fittings; line sets; brass and copper alloy rod, bar, and shapes; aluminum impact extrusions; plastic fittings and valves; refrigeration valves and fittings; fabricated tubular products; and steel nipples. The Company also resells imported brass and plastic plumbing valves, malleable iron fittings, faucets, and plumbing specialty products. Given the nature of the Company’s business and product offerings, sales transactions with customers are generally comprised of a single performance obligation that involves delivery of the products identified in the contracts with customers. Performance obligations are generally satisfied at the point in time of shipment and payment is generally due within sixty days. Variable consideration is estimated for future rebates on certain product lines and product returns. The Company records variable consideration as an adjustment to the transaction price in the period it is incurred. Since variable consideration is settled within a short period of time, the time value of money is not significant. The Company also evaluated specific contract terms, primarily within the Industrial Metals and Climate segments, related to the production of customized products and payment rights and determined that there are no significant changes to the timing or nature of revenue recognition under the ASU. As part of the overall evaluation of the standard, the Company has assessed and implemented necessary changes to its accounting policies, practices, and internal controls over financial reporting to support the standard. The Company adopted the ASU during the first quarter of 2018 using the modified retrospective method for all contracts with customers. The adoption did not result in a significant impact on opening retained earnings. Revenue for prior periods have not been adjusted and continue to be reported under Revenue Recognition (Topic 605) . No significant judgments were made in the application of the guidance in ASC 606 and there were no material contract assets, contract liabilities, or deferred contract costs as of September 29, 2018 . In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash . The ASU requires entities to report the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The Company adopted the ASU during the first quarter of 2018 using a retrospective approach for each period presented. Prior to the adoption of the ASU, the Company presented the change in restricted cash balances separately as a cash flow from investing activity. Upon adoption, the Company included restricted cash in each of the balances of the cash, cash equivalents, and restricted cash at the beginning and end of periods in the Condensed Consolidated Statements of Cash Flows. The prior period has been revised to conform to the current period presentation, and as a result, net cash flows for the nine months ended September 30, 2017 increased by $4.0 million . A reconciliation of cash, cash equivalents, and restricted cash as of September 29, 2018 and December 30, 2017 is as follows: (In thousands) September 29, December 30, Cash & cash equivalents $ 104,735 $ 120,269 Restricted cash included within other current assets 4,206 6,189 Restricted cash included within other assets 108 105 Total cash, cash equivalents, and restricted cash $ 109,049 $ 126,563 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. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory . The ASU requires companies to account for the income tax effects of intercompany transfers of assets other than inventory when the transfer occurs. Companies will still be required to defer the income tax effects of intercompany inventory transactions in an exception to the income tax accounting guidance. The Company adopted the ASU during the first quarter of 2018 and the adoption had no impact on its Condensed Consolidated Financial Statements. Issued 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 ASU will be effective for the annual period beginning in 2020. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements. 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 ASU will be effective for interim and annual periods beginning in 2020. An entity is permitted to early adopt either the entire standard or only the provisions that eliminate or modify requirements, and can elect to early adopt in interim periods. 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 should be applied retrospectively. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements and ASU No. 2018-10, Codification Improvements to Topic 842, Leases . The ASUs provide entities with relief from the costs of implementation and clarify how to apply certain aspects of the new leasing standard, ASC 842. ASC 842 requires an entity to recognize a right-of-use asset and lease liability for all leases with terms of more than 12 months. Recognition, measurement and presentation of expenses will depend on classification as a financing or operating lease. The guidance also require certain quantitative and qualitative disclosures about leasing arrangements. The ASU will be effective for interim and annual periods beginning in 2019. Early adoption is permitted. ASC 842 requires a modified retrospective adoption, but ASU 2018-11 amends ASC 842 so that entities may elect not to recast their comparative periods in transition and allows entities to change their date of initial application to the beginning of the period of adoption. The future minimum lease payments under noncancelable operating leases were approximately $40.5 million as of December 30, 2017. The Company is still evaluating the effects that the provisions of the ASUs and the ASC will have on its Condensed Consolidated Financial Statements.

Earnings per Common Share

Earnings per Common Share	9 Months Ended
	Sep. 29, 2018
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 result from the assumed exercise of outstanding stock options and vesting of restricted stock awards, computed using the treasury stock method. Approximately 79 thousand and 52 thousand stock-based awards were excluded from the computation of diluted earnings per share for the quarters ended September 29, 2018 and September 30, 2017 , respectively, because they were antidilutive.

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 29, 2018
Acquisitions and Dispositions [Abstract]
Acquisitions and Dispositions	Acquisitions and Dispositions Acquisitions ATCO On July 2, 2018, the Company entered into a stock purchase agreement pursuant to which the Company acquired all of the outstanding capital stock of ATCO Rubber Products, Inc. (ATCO) for approximately $156.7 million , net of working capital adjustments. The total purchase price consisted of $151.4 million in cash at closing and a contingent consideration arrangement which requires the Company to pay the former owner up to $12.0 million based on EBITDA growth of the acquired business. ATCO is an industry leader in the manufacturing and distribution of insulated HVAC flexible duct systems and will support the Company’s strategy to grow its Climate Products businesses to become a more valuable resource to its HVAC customers. The acquired business is reported in the Company’s Climate segment. The fair value of the assets acquired totaled $139.2 million , consisting primarily of property, plant, and equipment of $83.2 million , inventories of $33.1 million , accounts receivable of $21.8 million , other current assets of $0.8 million , and other assets of $0.3 million . The fair value of the liabilities assumed totaled $19.8 million , consisting primarily of accounts payable of $8.1 million , other current liabilities of $9.6 million , and other liabilities of $2.1 million . Of the remaining purchase price, $15.9 million was allocated to tax-deductible goodwill and $21.4 million was allocated to intangible assets, including technology, customer relationships, trade names, and supply contracts. The purchase price allocation is provisional as of September 29, 2018 and subject to change upon completion of the final valuation of the long-lived assets, working capital, and contingent consideration during the measurement period. ATCO had revenues of approximately $166.0 million in its fiscal year ending December 31, 2017. The following table presents condensed pro forma consolidated results of operations as if the ATCO acquisition has occurred at the beginning of the periods presented. The pro forma information does not purport to be indicative of the results that would have been obtained if the operations had actually been combined during the periods presented, and is not necessarily indicative of operating results to be expected in future periods. The most significant pro forma adjustments to the historical results of operations relate to the application of purchase accounting and financing structure. For the Nine Months Ended (In thousands, except per share data) September 29, 2018 September 30, 2017 Net sales $ 2,036,367 $ 1,868,677 Net income 84,823 82,523 Basic earnings per share $ 1.49 $ 1.45 Diluted earnings per share 1.48 1.44 Die-Mold On March 31, 2018, the Company entered into a share purchase agreement pursuant to which the Company acquired all of the outstanding shares of Die-Mold Tool Limited (Die-Mold) for approximately $ 13.6 million , net of working capital adjustments. The total purchase price consisted of $12.4 million in cash at closing and a contingent consideration arrangement which requires the Company to pay the former owner up to $2.3 million based on EBITDA growth of the acquired business. Die-Mold, based out of Ontario, Canada, is a manufacturer of plastic PEX and other plumbing-related fittings and an integrated designer and manufacturer of plastic injection tooling. The business complements the Company’s existing businesses within the Piping Systems segment. The fair value of the assets acquired totaled $7.0 million , consisting primarily of property, plant, and equipment of $3.3 million , inventories of $1.8 million , and accounts receivable of $1.7 million . The fair value of the liabilities assumed totaled $0.9 million , consisting primarily of accounts payable of $0.7 million and other current liabilities of $0.2 million . Of the remaining purchase price, $7.5 million was allocated to non-deductible goodwill and intangible assets. The purchase price allocation is provisional as of September 29, 2018 and subject to change upon completion of the final valuation of the long-lived assets and contingent consideration during the measurement period. Heatlink Group On May 31, 2017, the Company entered into a share purchase agreement pursuant to which the Company acquired all of the outstanding shares of Pexcor Manufacturing Company Inc. and Heatlink Group Inc. (collectively, Heatlink Group) for approximately $17.2 million , net of working capital adjustments. The total purchase price consisted of $16.3 million in cash at closing and a contingent consideration arrangement which requires the Company to pay the former owners up to $2.2 million based on the EBITDA growth of the acquired business. Heatlink Group, based out of Calgary, Alberta, Canada, produces and sells a complete line of products for PEX plumbing and radiant systems. The business complements the Company’s existing businesses within the Piping Systems segment. The fair value of the assets acquired totaled $9.9 million , consisting primarily of inventories of $4.6 million , accounts receivable of $2.8 million , property, plant, and equipment of $2.0 million , and other current assets of $0.5 million . The fair value of the liabilities assumed totaled $6.0 million , consisting primarily of accounts payable of $3.6 million , other current liabilities of $0.5 million , and deferred taxes of $1.9 million . Of the remaining purchase price, $13.3 million was allocated to non-deductible goodwill and intangible assets. The valuation of the business has been finalized. Changes to the purchase price allocation from the amounts presented in the Company’s 2017 Annual Report on Form 10-K included the valuation of the contingent consideration of $0.9 million and the recognition of a deferred tax liability of $1.9 million that resulted from a basis difference in the long-lived assets acquired. These changes resulted in an increase to goodwill. Disposition Mueller-Xingrong On June 21, 2017, the Company entered into a definitive equity transfer agreement with Jiangsu Xingrong Hi-Tech Co. Ltd. and Jiangsu Baiyang Industries Co. Ltd. (Baiyang), together, the minority partners in Mueller-Xingrong (the Company’s Chinese joint venture), pursuant to which the Company sold its 50.5 percent equity interest in Mueller-Xingrong to Baiyang for approximately $18.3 million . Mueller-Xingrong manufactures engineered copper tube primarily for air-conditioning applications in China and was included in the Piping Systems segment. Mueller-Xingrong reported net sales of $67.3 million and net losses of $9 thousand in 2017 . The carrying value of the assets disposed totaled $56.8 million , consisting primarily of accounts receivable, inventories, and long-lived assets. The carrying value of the liabilities disposed (consisting primarily of current debt and accounts payable), noncontrolling interest, and amounts recognized in accumulated other comprehensive income (AOCI) totaled $36.2 million . Since the disposal constituted a complete liquidation of the Company’s investment in a foreign entity, the Company removed from AOCI and recognized a cumulative translation gain of $3.8 million . As a result of the disposal, the Company recognized a net gain on the sale of this business of $1.5 million in the Condensed Consolidated Financial Statements for the nine months ended September 30, 2017 .

Segment Information

Segment Information	9 Months Ended
	Sep. 29, 2018
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, and 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., and the European Operations manufacture copper tube in the U.K. which is sold primarily in Europe. The Trading Group manufactures pipe nipples and imports 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, and ATCO. These domestic businesses manufacture and fabricate valves, assemblies, high pressure components, coaxial heat exchangers, and insulated HVAC flexible duct systems 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 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 410,525 $ 158,709 $ 81,619 $ (4,895 ) $ 645,958 Cost of goods sold 363,174 141,435 66,832 (4,485 ) 566,956 Depreciation and amortization 5,946 1,864 2,123 686 10,619 Selling, general, and administrative expense 17,387 3,086 6,890 11,526 38,889 (Gain) loss on sale of assets (1,390 ) (1,301 ) — — (2,691 ) Insurance recovery — (1,486 ) — — (1,486 ) Operating income 25,408 15,111 5,774 (12,622 ) 33,671 Interest expense (6,746 ) Other income (expense), net 411 Income before income taxes $ 27,336 For the Quarter Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 384,078 $ 147,578 $ 32,488 $ (13,781 ) $ 550,363 Cost of goods sold 340,191 120,021 24,111 (13,061 ) 471,262 Depreciation and amortization 5,290 1,845 636 495 8,266 Selling, general, and administrative expense 17,516 3,014 2,312 10,372 33,214 (Gain) loss on sale of assets 140 — — — 140 Operating income 20,941 22,698 5,429 (11,587 ) 37,481 Interest expense (5,237 ) Other loss, net (380 ) Income before income taxes $ 31,864 Segment information (continued): For the Nine Months Ended September 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,294,672 $ 511,932 $ 156,854 $ (14,667 ) $ 1,948,791 Cost of goods sold 1,120,890 445,259 124,806 (14,509 ) 1,676,446 Depreciation and amortization 17,568 5,715 3,371 2,427 29,081 Selling, general, and administrative expense 57,931 9,908 12,009 32,229 112,077 (Gain) loss on sale of assets (2,093 ) (1,301 ) — 3,060 (334 ) Insurance recovery — (1,486 ) — — (1,486 ) Operating income 100,376 53,837 16,668 (37,874 ) 133,007 Interest expense (18,728 ) Other income, net 1,557 Income before income taxes $ 115,836 For the Nine Months Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,205,697 $ 451,919 $ 103,403 $ (18,470 ) $ 1,742,549 Cost of goods sold 1,049,098 377,036 77,124 (19,258 ) 1,484,000 Depreciation and amortization 16,223 5,647 1,880 1,466 25,216 Selling, general, and administrative expense 55,133 9,802 7,244 32,497 104,676 Asset impairments 411 — — — 411 (Gain) loss on sale of assets (1,491 ) — — — (1,491 ) Operating income 86,323 59,434 17,155 (33,175 ) 129,737 Interest expense (14,210 ) Other income, net 556 Income before income taxes $ 116,083 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 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 340,269 $ — $ — $ 340,269 Brass rod and forgings — 122,411 — 122,411 OEM components, tube & assemblies 7,618 12,292 35,555 55,465 Valves and plumbing specialties 62,638 — — 62,638 Other — 24,006 46,064 70,070 410,525 158,709 81,619 650,853 Intersegment sales (4,895 ) Net sales $ 645,958 For the Quarter Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 319,115 $ — $ — $ 319,115 Brass rod and forgings — 112,592 — 112,592 OEM components, tube & assemblies 6,962 13,051 32,488 52,501 Valves and plumbing specialties 58,001 — — 58,001 Other — 21,935 — 21,935 384,078 147,578 32,488 564,144 Intersegment sales (13,781 ) Net sales $ 550,363 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,077,525 $ — $ — $ 1,077,525 Brass rod and forgings — 394,880 — 394,880 OEM components, tube & assemblies 22,128 41,956 110,790 174,874 Valves and plumbing specialties 195,019 — — 195,019 Other — 75,096 46,064 121,160 1,294,672 511,932 156,854 1,963,458 Intersegment sales (14,667 ) Net sales $ 1,948,791 For the Nine Months Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 945,914 $ — $ — $ 945,914 Brass rod and forgings — 346,555 — 346,555 OEM components, tube & assemblies 86,642 39,153 103,403 229,198 Valves and plumbing specialties 173,141 — — 173,141 Other — 66,211 — 66,211 1,205,697 451,919 103,403 1,761,019 Intersegment sales (18,470 ) Net sales $ 1,742,549

Inventories

Inventories	9 Months Ended
	Sep. 29, 2018
Inventory Disclosure [Abstract]
Inventories	Inventories (In thousands) September 29, December 30, Raw materials and supplies $ 87,605 $ 108,397 Work-in-process 61,138 46,158 Finished goods 171,725 180,143 Valuation reserves (7,072 ) (6,797 ) Inventories $ 313,396 $ 327,901

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 29, 2018
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 (i) a forecasted transaction or the variability of cash flow to be paid (cash flow hedge) or (ii) the fair value of a recognized asset or liability (fair value 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 a derivative that is qualified, designated, and highly effective as a fair value hedge, along with the gain or loss on the hedged recognized asset or liability that is attributable to the hedged risk, are recorded in current earnings. Changes in the fair value of undesignated derivatives executed as economic hedges and the ineffective portion of designated derivatives 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 29, 2018 , the Company held open futures contracts to purchase approximately $66.0 million of copper over the next 15 months related to fixed price sales orders. The fair value of those futures contracts was an $839 thousand net loss 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 29, 2018 , this amount was approximately $90 thousand of deferred net losses , net of tax. The Company may also enter into futures contracts to protect the value of inventory against market fluctuations. At September 29, 2018 , the Company held open futures contracts to sell approximately $4.5 million of copper over the next three months related to copper inventory. The fair value of those futures contracts was a $32 thousand net loss position, which was determined by obtaining quoted market prices (level 1 within the fair value hierarchy). The Company presents its derivative assets and liabilities in the Condensed Consolidated Balance Sheets on a net basis by counterparty. The following table summarizes the location and fair value of the derivative instruments and disaggregates the net derivative assets and liabilities into gross components on a contract-by-contract basis: Asset Derivatives Liability Derivatives Fair Value Fair Value (In thousands) Balance Sheet Location September 29, December 30, Balance Sheet Location September 29, December 30, Commodity contracts - gains Other current assets $ 207 $ 1,014 Other current liabilities $ 880 $ 55 Commodity contracts - losses Other current assets (127 ) (5 ) Other current liabilities (1,831 ) (3,210 ) Total derivatives (1) $ 80 $ 1,009 $ (951 ) $ (3,155 ) (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 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Fair value hedges: Gain on commodity contracts (qualifying) Cost of goods sold $ — $ — $ 391 $ — Loss on hedged item - inventory Cost of goods sold — — (385 ) — Undesignated derivatives: (Loss) gain on commodity contracts (nonqualifying) Cost of goods sold (2,848 ) (3,083 ) 5,579 (3,506 ) The following tables summarize amounts recognized in and reclassified from AOCI during the period: For the Quarter Ended September 29, 2018 (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 $ 305 Cost of goods sold $ (180 ) Other 6 Other — Total $ 311 Total $ (180 ) Changes recognized in and reclassified from AOCI (continued): For the Quarter Ended September 30, 2017 (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 $ (541 ) Cost of goods sold $ 237 Interest rate swap — Interest expense 149 Other 23 Other — Total $ (518 ) Total $ 386 For the Nine Months Ended September 29, 2018 (In thousands) 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 $ (438 ) Cost of goods sold $ (455 ) Other (3 ) Other — Total $ (441 ) Total $ (455 ) For the Nine Months Ended September 30, 2017 (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 $ (1,354 ) Cost of goods sold $ 913 Interest rate swap — Interest expense 447 Other 179 Other — Total $ (1,175 ) Total $ 1,360 The Company enters into futures and forward contracts that closely match the terms of the underlying transactions. As a result, the ineffective portion of the qualifying open hedge contracts through September 29, 2018 was not material to the Condensed Consolidated Statements of Income. 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 29, 2018 and December 30, 2017 , the Company had recorded restricted cash in other current assets of $3.4 million and $5.3 million , respectively, as collateral related to open derivative contracts under the master netting arrangements. Long-Term Debt The fair value of long-term debt at September 29, 2018 approximates the carrying value on that date. The estimated fair values were determined based on quoted market prices and the current rates offered for debt with similar terms and maturities. The fair value of long-term debt is classified as level 2 within the fair value hierarchy. This classification is defined as a fair value determined using market-based inputs other than quoted prices that are observable for the liability, either directly or indirectly.

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates	9 Months Ended
	Sep. 29, 2018
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’ 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. 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 29, December 30, Current assets $ 222,408 $ 246,127 Noncurrent assets 112,547 139,200 Current liabilities 163,931 174,710 Noncurrent liabilities 60,112 58,334 For the Quarter Ended For the Nine Months Ended (In thousands) September 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Net sales $ 131,827 $ 148,400 $ 382,132 $ 407,300 Gross profit 18,140 21,500 41,989 56,700 Net loss (5,007 ) (788 ) (22,867 ) (3,492 ) The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter ended September 29, 2018 included net losses of $2.5 million for Tecumseh. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the nine months ended September 29, 2018 included net losses of $15.4 million and charges of $3.0 million related to certain labor claim contingencies, offset by a gain of $7.0 million related to a settlement with the Brazilian Federal Revenue Agency for Tecumseh. Bahrain 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 will operate and brand its products under the Mueller Industries family of brands. The Company has invested approximately $4.5 million of cash to date and will be the technical and marketing lead in return for 40 percent ownership in the joint venture. The Company’s loss from unconsolidated affiliates, net of foreign tax, for the quarter and nine months ended September 29, 2018 included net losses of $0.5 million and $2.1 million , respectively, for Bahrain.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 29, 2018
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 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Pension benefits: Service cost $ 22 $ 35 $ 66 $ 106 Interest cost 1,478 1,659 4,436 4,977 Expected return on plan assets (2,290 ) (2,184 ) (6,869 ) (6,552 ) Amortization of net loss 293 536 877 1,608 Net periodic benefit (income) cost $ (497 ) $ 46 $ (1,490 ) $ 139 Other benefits: Service cost $ 59 $ 54 $ 175 $ 163 Interest cost 147 147 441 442 Amortization of prior service credit (226 ) (225 ) (677 ) (676 ) Amortization of net loss (gain) 14 (10 ) 43 (30 ) Net periodic benefit income $ (6 ) $ (34 ) $ (18 ) $ (101 ) The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 29, 2018
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. 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. 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 of a third party that the Company understands may owe indemnification obligations to one of the other PRPs 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. 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. The Company’s reserve for its proportionate share of the remediation costs associated with the 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 2029 to address residual discharges of acid rock drainage. The Company currently estimates that it will spend between approximately $12.8 million and $17.6 million for remediation at these sites over the next 30 years. 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 $3.0 million over the next 19 years. 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. These amounts are included in the Company’s reserve for environmental liabilities as of December 30, 2017. 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). 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 $0.8 million to $1.2 million over the next eight 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. Guarantees Guarantees, in the form of letters of credit, are issued by the Company generally to assure the payment of insurance deductibles and certain retiree health benefits. 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 29, 2018 were $8.5 million .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 29, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective tax rate for the third quarter of 2018 was 12 percent compared with 27 percent for the same period last year. The items impacting the effective tax rate for the third quarter of 2018 were primarily attributable to a reduction of $4.3 million , or seven cents per diluted share, related to the provisional transition tax calculation and the reduction for the impact of investments in unconsolidated affiliates of $0.7 million . These were partially offset by the provision for state income taxes, net of the federal benefit, of $0.7 million and an increase in valuation allowance of $1.5 million , or three cents per diluted share. The Company’s effective tax rate for the third quarter of 2017 was 27 percent . The items impacting the effective tax rate for the third quarter of 2017 were primarily attributable to reductions for the U.S. production activities deduction of $0.6 million , the effect of foreign tax rates lower than statutory tax rates of $1.6 million , and the tax benefit of equity compensation deductions of $0.5 million . The Company’s effective tax rate for the first nine months of 2018 was 20 percent compared with 29 percent for the same period last year. The items impacting the effective tax rate for the first nine months of 2018 were primarily attributable to a reduction of $4.3 million , or seven cents per diluted share, related to the provisional transition tax calculation and a reduction for the impact of investments in unconsolidated affiliates of $4.4 million . These were partially offset by the provision for state income taxes, net of the federal benefit, of $3.3 million , an increase in valuation allowance of $1.5 million , or three cents per diluted share, the effect of foreign tax rates different than statutory rates of $0.8 million , and the inclusion for global intangible low-taxed income (GILTI) of $0.8 million . The Company records the U.S. tax effects of its investment in Tecumseh, an unconsolidated affiliate, in income tax expense in the Condensed Consolidated Statements of Income. The Company’s effective tax rate for the first nine months of 2017 was 29 percent . The items impacting the effective tax rate for the first nine months of 2017 were primarily attributable to reductions for the U.S. production activities deduction of $2.4 million , the effect of foreign tax rates lower than statutory tax rates of $4.6 million , the tax benefit of equity compensation deductions of $2.2 million , and the impact of investments in unconsolidated affiliates of $0.9 million . These items were partially offset by the provision for state income taxes, net of the federal benefit, of $1.7 million . The Tax Cuts and Jobs Act (the Act) was enacted on December 22, 2017. The Act reduces the U.S. federal corporate income tax rate from 35 percent to 21 percent, requires companies to pay a one-time transition tax on the accumulated earnings of certain foreign subsidiaries, and creates new taxes on certain foreign-sourced earnings. The Company is applying the guidance in SAB 118 in accounting for the enactment date effects of the Act. At December 30, 2017, the Company made a reasonable estimate of the one-time transition tax on accumulated foreign earnings as well as the impact of the Act on its existing deferred tax balances. As discussed below, the Company has not completed its accounting for the tax effects of the Act as of September 29, 2018 . The one-time transition tax is based on the Company’s total post-1986 earnings and profits (E&P) for which the accrual of U.S. income taxes had previously been deferred. The Company recorded a provisional amount for its one-time transition tax liability of $12.9 million at December 30, 2017, and adjusted this amount to $8.6 million during the third quarter of 2018. The Company continues to refine its calculation of the total post-1986 foreign E&P for these foreign subsidiaries. Further, on August 1, 2018, the Treasury Department issued proposed regulations related to the calculation of the transition tax, and the Company is analyzing the impact of these regulations on the calculation of the transition tax. Accordingly, the Company’s estimate of the one-time transition tax may change when it finalizes the calculation of post-1986 foreign E&P previously deferred from U.S. federal taxation and finalizes its analysis of the regulations. At December 30, 2017, the Company remeasured certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future, which is generally 21 percent. A provisional tax benefit of $12.1 million was recorded, and no adjustment was recorded to this estimate in the current quarter. The Company is still analyzing certain aspects of the Act and refining its calculations, which could potentially affect the measurement of these balances. The GILTI provisions of the Act impose a tax on the GILTI earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740, No. 5, Accounting for Global Intangible Low-Taxed Income , states that an entity can make an accounting policy election to either recognize deferred taxes for temporary basis differences expected to reverse as GILTI in future years or provide for the tax expense related to GILTI in the year the tax is incurred. Given the complexity of the GILTI provisions, the Company is still evaluating the effects of these provisions and has not yet determined the new accounting policy. At September 29, 2018 , because the Company is still assessing the GILTI provisions and future income subject to the GILTI provisions, it has included an estimate of the tax on GILTI related to current-year operations in the forecasted effective tax rate and has not provided additional GILTI on deferred 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. 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. 29, 2018
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, unrealized gains and losses on marketable securities classified as available-for-sale, 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 29, 2018 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Unrealized Gain on Equity Securities Attributable to Unconsol. Affiliates Total Balance as of December 30, 2017 $ (38,163 ) $ 847 $ (20,610 ) $ — $ 6,870 $ (51,056 ) Other comprehensive (loss) income before reclassifications (5,143 ) (441 ) 551 — (7,187 ) (12,220 ) Amounts reclassified from AOCI — (455 ) 218 — — (237 ) Net current-period other comprehensive (loss) income (5,143 ) (896 ) 769 — (7,187 ) (12,457 ) Reclassification of stranded effects of the Act — 112 (1,018 ) — 1,462 556 Balance as of September 29, 2018 $ (43,306 ) $ 63 $ (20,859 ) $ — $ 1,145 $ (62,957 ) For the Nine Months Ended September 30, 2017 (In thousands) Cumulative Translation Adjustment Unrealized (Loss) Gain on Derivatives Pension/OPEB Liability Adjustment Unrealized Gain (Loss) on Equity Securities Attributable to Unconsol. Affiliates Total Balance as of December 31, 2016 $ (49,965 ) $ (300 ) $ (23,046 ) $ 380 $ 5,975 $ (66,956 ) Other comprehensive income (loss) before reclassifications 18,209 (1,175 ) (1,309 ) (1 ) (1,086 ) 14,638 Amounts reclassified from AOCI (3,777 ) 1,360 737 (379 ) — (2,059 ) Net current-period other comprehensive income (loss) 14,432 185 (572 ) (380 ) (1,086 ) 12,579 Balance as of September 30, 2017 $ (35,533 ) $ (115 ) $ (23,618 ) $ — $ 4,889 $ (54,377 ) Reclassification adjustments out of AOCI were as follows: Amount reclassified from AOCI For the Quarter Ended For the Nine Months Ended (In thousands) September 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Affected line item Unrealized losses (gains) on derivatives: Commodity contracts $ (204 ) $ 223 $ (550 ) $ 1,247 Cost of goods sold Interest rate swap — 232 — 696 Interest expense 24 (69 ) 95 (583 ) Income tax expense (benefit) $ (180 ) $ 386 $ (455 ) $ 1,360 Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 81 $ 301 $ 243 $ 902 Other income, net (9 ) (55 ) (25 ) (165 ) Income tax benefit $ 72 $ 246 $ 218 $ 737 Net of tax and noncontrolling interests Sale of available-for-sale securities $ — $ — $ — $ (611 ) Other income, net $ — $ — $ — $ 232 Income tax expense $ — $ — $ — $ (379 ) Net of tax and noncontrolling interests Gain recognized upon sale of business $ — $ — $ — $ (3,777 ) Gain on sale of assets $ — $ — $ — $ — Income tax expense $ — $ — $ — $ (3,777 ) Net of tax and noncontrolling interests

Noncontrolling Interests

Noncontrolling Interests	9 Months Ended
	Sep. 29, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interests	Noncontrolling Interests (In thousands) Noncontrolling Interests Balance as of December 30, 2017 $ 13,917 Dividends paid to noncontrolling interests (592 ) Net income attributable to noncontrolling interests 1,487 Other comprehensive income attributable to noncontrolling interests, net of tax: Foreign currency translation (390 ) Balance as of September 29, 2018 $ 14,422

Recent Accounting Standards (Po

Recent Accounting Standards (Policies)	9 Months Ended
	Sep. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Standards	Adopted In February 2018, the Financial Accounting Standards Board (FASB) issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (AOCI) . The ASU permits entities to reclassify tax effects stranded in AOCI as a result of tax reform to retained earnings. The guidance is effective for the Company in interim and annual periods beginning in 2019. Early adoption is permitted and can be applied retrospectively or in the period of adoption. The Company early adopted the ASU during the first quarter of 2018, which resulted in a net reclassification of $556 thousand from AOCI to retained earnings during the quarter. In March 2017, the FASB issued ASU No. 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost . The ASU requires employers that sponsor defined benefit pension and/or other postretirement benefit plans to present the service cost component of net periodic benefit cost in the same income statement line item(s) as other employee compensation costs arising from services rendered during the period and other components of net periodic benefits cost separately from the line item(s) that includes the service cost and outside of any subtotal of operating income. The Company adopted the ASU during the first quarter of 2018 using a retrospective approach for each period presented, and elected to use the practical expedient that allows the Company to use the amounts previously presented in its Benefit Plans disclosure as the estimation basis for applying the retrospective presentation requirements. Prior to the adoption of the ASU, net periodic benefit cost (income) was reported within selling, general, and administrative expense in the Condensed Consolidated Statements of Income. The prior periods have been revised to conform to the current period presentation, resulting in the reclassification of $78 thousand and $232 thousand of net periodic benefit income from operating income to other income (expense), net for the quarter and nine months ended September 30, 2017 , respectively. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business . The ASU provides guidance to assist entities in evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The updated guidance requires prospective adoption. Early adoption is permitted. The Company early adopted the ASU during the first quarter of 2018 and the adoption had no impact on its Condensed Consolidated Financial Statements. In December 2016, the FASB issued ASU No. 2016-20, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers . The ASU provides correction or improvement to the guidance previously issued in Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers . Under the ASU, an entity will recognize revenue to depict the transfer of promised goods or services to customers at an amount that reflects the consideration that it expects to receive in exchange for the goods or services. It also requires more detailed disclosures to enable users of financial statements to understand the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The ASU requires revenue to be recognized over time (i.e., throughout the production process) rather than at a point in time (generally upon shipment to the customer) if performance does not create an asset with an alternative use to the entity and the entity has an enforceable right to payment for performance completed to date. The Company generates revenue through the manufacture and sale of copper tube and fittings; line sets; brass and copper alloy rod, bar, and shapes; aluminum impact extrusions; plastic fittings and valves; refrigeration valves and fittings; fabricated tubular products; and steel nipples. The Company also resells imported brass and plastic plumbing valves, malleable iron fittings, faucets, and plumbing specialty products. Given the nature of the Company’s business and product offerings, sales transactions with customers are generally comprised of a single performance obligation that involves delivery of the products identified in the contracts with customers. Performance obligations are generally satisfied at the point in time of shipment and payment is generally due within sixty days. Variable consideration is estimated for future rebates on certain product lines and product returns. The Company records variable consideration as an adjustment to the transaction price in the period it is incurred. Since variable consideration is settled within a short period of time, the time value of money is not significant. The Company also evaluated specific contract terms, primarily within the Industrial Metals and Climate segments, related to the production of customized products and payment rights and determined that there are no significant changes to the timing or nature of revenue recognition under the ASU. As part of the overall evaluation of the standard, the Company has assessed and implemented necessary changes to its accounting policies, practices, and internal controls over financial reporting to support the standard. The Company adopted the ASU during the first quarter of 2018 using the modified retrospective method for all contracts with customers. The adoption did not result in a significant impact on opening retained earnings. Revenue for prior periods have not been adjusted and continue to be reported under Revenue Recognition (Topic 605) . No significant judgments were made in the application of the guidance in ASC 606 and there were no material contract assets, contract liabilities, or deferred contract costs as of September 29, 2018 . In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash . The ASU requires entities to report the changes in the total of cash, cash equivalents, restricted cash, and restricted cash equivalents in the statement of cash flows. As a result, entities will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents in the statement of cash flows. The Company adopted the ASU during the first quarter of 2018 using a retrospective approach for each period presented. Prior to the adoption of the ASU, the Company presented the change in restricted cash balances separately as a cash flow from investing activity. Upon adoption, the Company included restricted cash in each of the balances of the cash, cash equivalents, and restricted cash at the beginning and end of periods in the Condensed Consolidated Statements of Cash Flows. The prior period has been revised to conform to the current period presentation, and as a result, net cash flows for the nine months ended September 30, 2017 increased by $4.0 million . A reconciliation of cash, cash equivalents, and restricted cash as of September 29, 2018 and December 30, 2017 is as follows: (In thousands) September 29, December 30, Cash & cash equivalents $ 104,735 $ 120,269 Restricted cash included within other current assets 4,206 6,189 Restricted cash included within other assets 108 105 Total cash, cash equivalents, and restricted cash $ 109,049 $ 126,563 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. In October 2016, the FASB issued ASU No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory . The ASU requires companies to account for the income tax effects of intercompany transfers of assets other than inventory when the transfer occurs. Companies will still be required to defer the income tax effects of intercompany inventory transactions in an exception to the income tax accounting guidance. The Company adopted the ASU during the first quarter of 2018 and the adoption had no impact on its Condensed Consolidated Financial Statements. Issued 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 ASU will be effective for the annual period beginning in 2020. The updated guidance requires retrospective adoption, and early adoption is permitted. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements. 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 ASU will be effective for interim and annual periods beginning in 2020. An entity is permitted to early adopt either the entire standard or only the provisions that eliminate or modify requirements, and can elect to early adopt in interim periods. 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 should be applied retrospectively. The Company does not expect the adoption of the ASU to have a material impact on its Condensed Consolidated Financial Statements. In July 2018, the FASB issued ASU No. 2018-11, Leases (Topic 842): Targeted Improvements and ASU No. 2018-10, Codification Improvements to Topic 842, Leases . The ASUs provide entities with relief from the costs of implementation and clarify how to apply certain aspects of the new leasing standard, ASC 842. ASC 842 requires an entity to recognize a right-of-use asset and lease liability for all leases with terms of more than 12 months. Recognition, measurement and presentation of expenses will depend on classification as a financing or operating lease. The guidance also require certain quantitative and qualitative disclosures about leasing arrangements. The ASU will be effective for interim and annual periods beginning in 2019. Early adoption is permitted. ASC 842 requires a modified retrospective adoption, but ASU 2018-11 amends ASC 842 so that entities may elect not to recast their comparative periods in transition and allows entities to change their date of initial application to the beginning of the period of adoption. The future minimum lease payments under noncancelable operating leases were approximately $40.5 million as of December 30, 2017. The Company is still evaluating the effects that the provisions of the ASUs and the ASC will have on its Condensed Consolidated Financial Statements.

Recent Accounting Standards (Ta

Recent Accounting Standards (Tables)	9 Months Ended
	Sep. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Schedule of Cash, Cash Equivalents and Restricted Cash	A reconciliation of cash, cash equivalents, and restricted cash as of September 29, 2018 and December 30, 2017 is as follows: (In thousands) September 29, December 30, Cash & cash equivalents $ 104,735 $ 120,269 Restricted cash included within other current assets 4,206 6,189 Restricted cash included within other assets 108 105 Total cash, cash equivalents, and restricted cash $ 109,049 $ 126,563
Schedule of Cash, Cash Equivalents and Restricted Cash	A reconciliation of cash, cash equivalents, and restricted cash as of September 29, 2018 and December 30, 2017 is as follows: (In thousands) September 29, December 30, Cash & cash equivalents $ 104,735 $ 120,269 Restricted cash included within other current assets 4,206 6,189 Restricted cash included within other assets 108 105 Total cash, cash equivalents, and restricted cash $ 109,049 $ 126,563

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	9 Months Ended
	Sep. 29, 2018
Acquisitions and Dispositions [Abstract]
Summary of Condensed Pro Forma Consolidated Results of Operations as if Acquisition Occurred at Beginning of Period	The following table presents condensed pro forma consolidated results of operations as if the ATCO acquisition has occurred at the beginning of the periods presented. The pro forma information does not purport to be indicative of the results that would have been obtained if the operations had actually been combined during the periods presented, and is not necessarily indicative of operating results to be expected in future periods. The most significant pro forma adjustments to the historical results of operations relate to the application of purchase accounting and financing structure. For the Nine Months Ended (In thousands, except per share data) September 29, 2018 September 30, 2017 Net sales $ 2,036,367 $ 1,868,677 Net income 84,823 82,523 Basic earnings per share $ 1.49 $ 1.45 Diluted earnings per share 1.48 1.44

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 29, 2018
Segment Reporting [Abstract]
Summary of Segment Information	Summarized segment information is as follows: For the Quarter Ended September 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 410,525 $ 158,709 $ 81,619 $ (4,895 ) $ 645,958 Cost of goods sold 363,174 141,435 66,832 (4,485 ) 566,956 Depreciation and amortization 5,946 1,864 2,123 686 10,619 Selling, general, and administrative expense 17,387 3,086 6,890 11,526 38,889 (Gain) loss on sale of assets (1,390 ) (1,301 ) — — (2,691 ) Insurance recovery — (1,486 ) — — (1,486 ) Operating income 25,408 15,111 5,774 (12,622 ) 33,671 Interest expense (6,746 ) Other income (expense), net 411 Income before income taxes $ 27,336 For the Quarter Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 384,078 $ 147,578 $ 32,488 $ (13,781 ) $ 550,363 Cost of goods sold 340,191 120,021 24,111 (13,061 ) 471,262 Depreciation and amortization 5,290 1,845 636 495 8,266 Selling, general, and administrative expense 17,516 3,014 2,312 10,372 33,214 (Gain) loss on sale of assets 140 — — — 140 Operating income 20,941 22,698 5,429 (11,587 ) 37,481 Interest expense (5,237 ) Other loss, net (380 ) Income before income taxes $ 31,864 Segment information (continued): For the Nine Months Ended September 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,294,672 $ 511,932 $ 156,854 $ (14,667 ) $ 1,948,791 Cost of goods sold 1,120,890 445,259 124,806 (14,509 ) 1,676,446 Depreciation and amortization 17,568 5,715 3,371 2,427 29,081 Selling, general, and administrative expense 57,931 9,908 12,009 32,229 112,077 (Gain) loss on sale of assets (2,093 ) (1,301 ) — 3,060 (334 ) Insurance recovery — (1,486 ) — — (1,486 ) Operating income 100,376 53,837 16,668 (37,874 ) 133,007 Interest expense (18,728 ) Other income, net 1,557 Income before income taxes $ 115,836 For the Nine Months Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Corporate and Eliminations Total Net sales $ 1,205,697 $ 451,919 $ 103,403 $ (18,470 ) $ 1,742,549 Cost of goods sold 1,049,098 377,036 77,124 (19,258 ) 1,484,000 Depreciation and amortization 16,223 5,647 1,880 1,466 25,216 Selling, general, and administrative expense 55,133 9,802 7,244 32,497 104,676 Asset impairments 411 — — — 411 (Gain) loss on sale of assets (1,491 ) — — — (1,491 ) Operating income 86,323 59,434 17,155 (33,175 ) 129,737 Interest expense (14,210 ) Other income, net 556 Income before income taxes $ 116,083
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 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 340,269 $ — $ — $ 340,269 Brass rod and forgings — 122,411 — 122,411 OEM components, tube & assemblies 7,618 12,292 35,555 55,465 Valves and plumbing specialties 62,638 — — 62,638 Other — 24,006 46,064 70,070 410,525 158,709 81,619 650,853 Intersegment sales (4,895 ) Net sales $ 645,958 For the Quarter Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 319,115 $ — $ — $ 319,115 Brass rod and forgings — 112,592 — 112,592 OEM components, tube & assemblies 6,962 13,051 32,488 52,501 Valves and plumbing specialties 58,001 — — 58,001 Other — 21,935 — 21,935 384,078 147,578 32,488 564,144 Intersegment sales (13,781 ) Net sales $ 550,363 Disaggregation of revenue from contracts with customers (continued): For the Nine Months Ended September 29, 2018 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 1,077,525 $ — $ — $ 1,077,525 Brass rod and forgings — 394,880 — 394,880 OEM components, tube & assemblies 22,128 41,956 110,790 174,874 Valves and plumbing specialties 195,019 — — 195,019 Other — 75,096 46,064 121,160 1,294,672 511,932 156,854 1,963,458 Intersegment sales (14,667 ) Net sales $ 1,948,791 For the Nine Months Ended September 30, 2017 (In thousands) Piping Systems Industrial Metals Climate Total Tube and fittings $ 945,914 $ — $ — $ 945,914 Brass rod and forgings — 346,555 — 346,555 OEM components, tube & assemblies 86,642 39,153 103,403 229,198 Valves and plumbing specialties 173,141 — — 173,141 Other — 66,211 — 66,211 1,205,697 451,919 103,403 1,761,019 Intersegment sales (18,470 ) Net sales $ 1,742,549

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 29, 2018
Inventory Disclosure [Abstract]
Inventories	(In thousands) September 29, December 30, Raw materials and supplies $ 87,605 $ 108,397 Work-in-process 61,138 46,158 Finished goods 171,725 180,143 Valuation reserves (7,072 ) (6,797 ) Inventories $ 313,396 $ 327,901

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 29, 2018
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 29, December 30, Balance Sheet Location September 29, December 30, Commodity contracts - gains Other current assets $ 207 $ 1,014 Other current liabilities $ 880 $ 55 Commodity contracts - losses Other current assets (127 ) (5 ) Other current liabilities (1,831 ) (3,210 ) Total derivatives (1) $ 80 $ 1,009 $ (951 ) $ (3,155 ) (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 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Fair value hedges: Gain on commodity contracts (qualifying) Cost of goods sold $ — $ — $ 391 $ — Loss on hedged item - inventory Cost of goods sold — — (385 ) — Undesignated derivatives: (Loss) gain on commodity contracts (nonqualifying) Cost of goods sold (2,848 ) (3,083 ) 5,579 (3,506 )
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 29, 2018 (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 $ 305 Cost of goods sold $ (180 ) Other 6 Other — Total $ 311 Total $ (180 ) Changes recognized in and reclassified from AOCI (continued): For the Quarter Ended September 30, 2017 (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 $ (541 ) Cost of goods sold $ 237 Interest rate swap — Interest expense 149 Other 23 Other — Total $ (518 ) Total $ 386 For the Nine Months Ended September 29, 2018 (In thousands) 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 $ (438 ) Cost of goods sold $ (455 ) Other (3 ) Other — Total $ (441 ) Total $ (455 ) For the Nine Months Ended September 30, 2017 (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 $ (1,354 ) Cost of goods sold $ 913 Interest rate swap — Interest expense 447 Other 179 Other — Total $ (1,175 ) Total $ 1,360

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)	9 Months Ended
	Sep. 29, 2018
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 29, December 30, Current assets $ 222,408 $ 246,127 Noncurrent assets 112,547 139,200 Current liabilities 163,931 174,710 Noncurrent liabilities 60,112 58,334 For the Quarter Ended For the Nine Months Ended (In thousands) September 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Net sales $ 131,827 $ 148,400 $ 382,132 $ 407,300 Gross profit 18,140 21,500 41,989 56,700 Net loss (5,007 ) (788 ) (22,867 ) (3,492 )

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 29, 2018
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 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Pension benefits: Service cost $ 22 $ 35 $ 66 $ 106 Interest cost 1,478 1,659 4,436 4,977 Expected return on plan assets (2,290 ) (2,184 ) (6,869 ) (6,552 ) Amortization of net loss 293 536 877 1,608 Net periodic benefit (income) cost $ (497 ) $ 46 $ (1,490 ) $ 139 Other benefits: Service cost $ 59 $ 54 $ 175 $ 163 Interest cost 147 147 441 442 Amortization of prior service credit (226 ) (225 ) (677 ) (676 ) Amortization of net loss (gain) 14 (10 ) 43 (30 ) Net periodic benefit income $ (6 ) $ (34 ) $ (18 ) $ (101 )

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 29, 2018
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 29, 2018 (In thousands) Cumulative Translation Adjustment Unrealized Gain (Loss) on Derivatives Pension/OPEB Liability Adjustment Unrealized Gain on Equity Securities Attributable to Unconsol. Affiliates Total Balance as of December 30, 2017 $ (38,163 ) $ 847 $ (20,610 ) $ — $ 6,870 $ (51,056 ) Other comprehensive (loss) income before reclassifications (5,143 ) (441 ) 551 — (7,187 ) (12,220 ) Amounts reclassified from AOCI — (455 ) 218 — — (237 ) Net current-period other comprehensive (loss) income (5,143 ) (896 ) 769 — (7,187 ) (12,457 ) Reclassification of stranded effects of the Act — 112 (1,018 ) — 1,462 556 Balance as of September 29, 2018 $ (43,306 ) $ 63 $ (20,859 ) $ — $ 1,145 $ (62,957 ) For the Nine Months Ended September 30, 2017 (In thousands) Cumulative Translation Adjustment Unrealized (Loss) Gain on Derivatives Pension/OPEB Liability Adjustment Unrealized Gain (Loss) on Equity Securities Attributable to Unconsol. Affiliates Total Balance as of December 31, 2016 $ (49,965 ) $ (300 ) $ (23,046 ) $ 380 $ 5,975 $ (66,956 ) Other comprehensive income (loss) before reclassifications 18,209 (1,175 ) (1,309 ) (1 ) (1,086 ) 14,638 Amounts reclassified from AOCI (3,777 ) 1,360 737 (379 ) — (2,059 ) Net current-period other comprehensive income (loss) 14,432 185 (572 ) (380 ) (1,086 ) 12,579 Balance as of September 30, 2017 $ (35,533 ) $ (115 ) $ (23,618 ) $ — $ 4,889 $ (54,377 )
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 29, 2018 September 30, 2017 September 29, 2018 September 30, 2017 Affected line item Unrealized losses (gains) on derivatives: Commodity contracts $ (204 ) $ 223 $ (550 ) $ 1,247 Cost of goods sold Interest rate swap — 232 — 696 Interest expense 24 (69 ) 95 (583 ) Income tax expense (benefit) $ (180 ) $ 386 $ (455 ) $ 1,360 Net of tax and noncontrolling interests Amortization of net loss and prior service cost on employee benefit plans $ 81 $ 301 $ 243 $ 902 Other income, net (9 ) (55 ) (25 ) (165 ) Income tax benefit $ 72 $ 246 $ 218 $ 737 Net of tax and noncontrolling interests Sale of available-for-sale securities $ — $ — $ — $ (611 ) Other income, net $ — $ — $ — $ 232 Income tax expense $ — $ — $ — $ (379 ) Net of tax and noncontrolling interests Gain recognized upon sale of business $ — $ — $ — $ (3,777 ) Gain on sale of assets $ — $ — $ — $ — Income tax expense $ — $ — $ — $ (3,777 ) Net of tax and noncontrolling interests

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 29, 2018
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interests	(In thousands) Noncontrolling Interests Balance as of December 30, 2017 $ 13,917 Dividends paid to noncontrolling interests (592 ) Net income attributable to noncontrolling interests 1,487 Other comprehensive income attributable to noncontrolling interests, net of tax: Foreign currency translation (390 ) Balance as of September 29, 2018 $ 14,422

Recent Accounting Standards - A

Recent Accounting Standards - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017		Dec. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of stranded effects of the Act	$ 556
Increase in cash flows			$ (17,514)	$ (250,162)	[1]
Future minimum lease payments under noncancelable operating leases						$ 40,500
ASU 2016-18 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in cash flows				4,000
Operating Income [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of net periodic benefit income		$ 78		232
Other Income [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of net periodic benefit income		$ (78)		$ (232)
[1]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

Recent Accounting Standards - R

Recent Accounting Standards - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017	Sep. 30, 2017	[1]	Dec. 31, 2016	[1]
Accounting Changes and Error Corrections [Abstract]
Cash & cash equivalents	$ 104,735	$ 120,269
Restricted cash included within other current assets	4,206	6,189
Restricted cash included within other assets	108	105
Total cash, cash equivalents, and restricted cash	$ 109,049	$ 126,563	$ 110,307		$ 360,469
[1]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

Earnings per Common Share (Deta

Earnings per Common Share (Details) - shares shares in Thousands	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Stock-based awards excluded from the computation of diluted earnings per share (in shares)	79	52

Acquisitions and Dispositions -

Acquisitions and Dispositions - Acquisitions (Details) - USD ($) $ in Millions	Jul. 02, 2018	Mar. 31, 2018	May 31, 2017
ATCO [Member]
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments	$ 156.7
Cash portion of acquisition price	151.4
Maximum possible contingent consideration	12
Fair value of assets acquired	139.2
Fair value of property, plant and equipment acquired	83.2
Fair value of inventories acquired	33.1
Fair value of accounts receivable acquired	21.8
Fair value of other current assets acquired	0.8
Fair value of other assets acquired	0.3
Fair value of liabilities acquired	19.8
Fair value of accounts payable acquired	8.1
Fair value of other current liabilities acquired	9.6
Fair value of other liabilities acquired	2.1
Tax-deductible goodwill	15.9
Fair value of intangible assets acquired	21.4
Revenues of acquired entity for last annual period	$ 166
Die-Mold [Member]
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments		$ 13.6
Cash portion of acquisition price		12.4
Maximum possible contingent consideration		2.3
Fair value of assets acquired		7
Fair value of property, plant and equipment acquired		3.3
Fair value of inventories acquired		1.8
Fair value of accounts receivable acquired		1.7
Fair value of liabilities acquired		0.9
Fair value of accounts payable acquired		0.7
Fair value of other current liabilities acquired		0.2
Allocation to non-deductible goodwill and intangible assets		$ 7.5
Pexcor/Heatlink [Member]
Business Acquisition [Line Items]
Consideration transferred net of working capital adjustments			$ 17.2
Cash portion of acquisition price			16.3
Maximum possible contingent consideration			2.2
Fair value of assets acquired			9.9
Fair value of property, plant and equipment acquired			2
Fair value of inventories acquired			4.6
Fair value of accounts receivable acquired			2.8
Fair value of other current assets acquired			0.5
Fair value of liabilities acquired			6
Fair value of accounts payable acquired			3.6
Fair value of other current liabilities acquired			0.5
Allocation to non-deductible goodwill and intangible assets			13.3
Fair value of deferred taxes acquired			1.9
Valuation of contingent consideration			$ 0.9

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Condensed Pro Forma Consolidated Results of Operations (Details) - ATCO [Member] - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Net sales	$ 2,036,367	$ 1,868,677
Net income	$ 84,823	$ 82,523
Basic earnings per share (in dollars per share)	$ 1.49	$ 1.45
Diluted earnings per share (in dollars per share)	$ 1.48	$ 1.44

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Disposition (Details) - USD ($) $ in Thousands	Jun. 21, 2017	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017		Dec. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss		$ 5,007	$ 788	$ 22,867	$ 3,492
Gain on sale of business				$ 0	1,491	[1]
Mueller-Xingrong [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage	50.50%
Net sales							$ 67,300
Net loss							$ 9
Mueller-Xingrong [Member] | Disposed of by sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of interest in joint venture	$ 18,300
Assets disposed of	56,800
Liabilities disposed of	36,200
Cumulative translation gain as a result of sale	$ 3,800
Gain on sale of business			$ 1,500		$ 1,500
[1]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

Segment Information - Summary o

Segment Information - Summary of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017		Sep. 29, 2018	Sep. 30, 2017
Summary of segment information [Abstract]
Net sales	$ 645,958	$ 550,363	[1]	$ 1,948,791	$ 1,742,549	[1]
Cost of goods sold	566,956	471,262	[1]	1,676,446	1,484,000	[1]
Depreciation and amortization	10,619	8,266	[1]	29,081	25,216	[1]
Selling, general, and administrative expense	38,889	33,214	[1]	112,077	104,676	[1]
Asset impairments	0	0	[1]	0	411	[1],[2]
(Gain) loss on sale of assets	(2,691)	140	[1]	(334)	(1,491)	[1]
Insurance recovery	(1,486)	0	[1]	(1,486)	0	[1],[2]
Operating income	33,671	37,481	[1]	133,007	129,737	[1]
Interest expense	(6,746)	(5,237)	[1]	(18,728)	(14,210)	[1]
Other income (expense), net	411	(380)	[1]	1,557	556	[1]
Income before income taxes	27,336	31,864	[1]	115,836	116,083	[1]
Operating Segments [Member]
Summary of segment information [Abstract]
Net sales	650,853	564,144		1,963,458	1,761,019
Operating Segments [Member] | Piping Systems [Member]
Summary of segment information [Abstract]
Net sales	410,525	384,078		1,294,672	1,205,697
Cost of goods sold	363,174	340,191		1,120,890	1,049,098
Depreciation and amortization	5,946	5,290		17,568	16,223
Selling, general, and administrative expense	17,387	17,516		57,931	55,133
Asset impairments					411
(Gain) loss on sale of assets	(1,390)	140		(2,093)	(1,491)
Insurance recovery	0			0
Operating income	25,408	20,941		100,376	86,323
Operating Segments [Member] | Industrial Metals [Member]
Summary of segment information [Abstract]
Net sales	158,709	147,578		511,932	451,919
Cost of goods sold	141,435	120,021		445,259	377,036
Depreciation and amortization	1,864	1,845		5,715	5,647
Selling, general, and administrative expense	3,086	3,014		9,908	9,802
Asset impairments					0
(Gain) loss on sale of assets	(1,301)	0		(1,301)	0
Insurance recovery	(1,486)			(1,486)
Operating income	15,111	22,698		53,837	59,434
Operating Segments [Member] | Climate [Member]
Summary of segment information [Abstract]
Net sales	81,619	32,488		156,854	103,403
Cost of goods sold	66,832	24,111		124,806	77,124
Depreciation and amortization	2,123	636		3,371	1,880
Selling, general, and administrative expense	6,890	2,312		12,009	7,244
Asset impairments					0
(Gain) loss on sale of assets	0	0		0	0
Insurance recovery	0			0
Operating income	5,774	5,429		16,668	17,155
Corporate and Eliminations [Member]
Summary of segment information [Abstract]
Net sales	(4,895)	(13,781)		(14,667)	(18,470)
Cost of goods sold	(4,485)	(13,061)		(14,509)	(19,258)
Depreciation and amortization	686	495		2,427	1,466
Selling, general, and administrative expense	11,526	10,372		32,229	32,497
Asset impairments					0
(Gain) loss on sale of assets	0	0		3,060	0
Insurance recovery	0			0
Operating income	$ (12,622)	$ (11,587)		$ (37,874)	$ (33,175)
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.
[2]	The Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2017 has been adjusted to reflect the adoption of ASU 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash. The Condensed Consolidated Statements of Cash Flows reflects the changes during the periods in the total of cash, cash equivalents, and restricted cash. Therefore, restricted cash activity is included with cash when reconciling the beginning-of-period and end-of-period total amounts shown. Refer to Note 1 for further discussion.

Segment Information - Net Sales

Segment Information - Net Sales by Major Product Line (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017		Sep. 29, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 645,958	$ 550,363	[1]	$ 1,948,791	$ 1,742,549	[1]
Operating Segments [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	650,853	564,144		1,963,458	1,761,019
Operating Segments [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	410,525	384,078		1,294,672	1,205,697
Operating Segments [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	158,709	147,578		511,932	451,919
Operating Segments [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	81,619	32,488		156,854	103,403
Operating Segments [Member] | Tube and fittings [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	340,269	319,115		1,077,525	945,914
Operating Segments [Member] | Tube and fittings [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	340,269	319,115		1,077,525	945,914
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	122,411	112,592		394,880	346,555
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	122,411	112,592		394,880	346,555
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	55,465	52,501		174,874	229,198
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	7,618	6,962		22,128	86,642
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	12,292	13,051		41,956	39,153
Operating Segments [Member] | OEM components, tube and assemblies [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	35,555	32,488		110,790	103,403
Operating Segments [Member] | Valves and plumbing specialties [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	62,638	58,001		195,019	173,141
Operating Segments [Member] | Valves and plumbing specialties [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	62,638	58,001		195,019	173,141
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 products [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	70,070	21,935		121,160	66,211
Operating Segments [Member] | Other products [Member] | Piping Systems [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	0	0		0	0
Operating Segments [Member] | Other products [Member] | Industrial Metals [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	24,006	21,935		75,096	66,211
Operating Segments [Member] | Other products [Member] | Climate [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	46,064	0		46,064	0
Intersegment Sales [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ (4,895)	$ (13,781)		$ (14,667)	$ (18,470)
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 87,605	$ 108,397
Work-in-process	61,138	46,158
Finished goods	171,725	180,143
Valuation reserves	(7,072)	(6,797)
Inventories	$ 313,396	$ 327,901

Financial Instruments - Additio

Financial Instruments - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Dec. 30, 2017
Derivative [Line Items]
Restricted cash in other current assets as collateral related to open derivative contracts	$ 3,400	$ 5,300
Commodity Contracts [Member]
Derivative [Line Items]
Deferred net losses, net of tax, included in AOCI	90
Cash Flow Hedging [Member] | Commodity Contracts [Member] | Long [Member]
Derivative [Line Items]
Open option contracts written, at fair value	$ 66,000
Time period for open copper future contract purchases	15 months
Fair value of future contracts with net loss position	$ 839
Fair Value Hedging [Member] | Commodity Contracts [Member] | Short [Member]
Derivative [Line Items]
Fair value of future contracts with net loss position	32
Open future contracts to sell copper	$ 4,500
Time period for open copper future contract sales	3 months

Financial Instruments - Summary

Financial Instruments - Summary of Location and Fair Value (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Sep. 29, 2018	Dec. 30, 2017
Derivatives, Fair Value [Line Items]
Total derivative assets	$ 80	$ 1,009
Total derivative liabilities	(951)	(3,155)
Other Current Assets [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Other current assets: Gain positions	207	1,014
Other current assets: Loss positions	(127)	(5)
Other Current Liabilities [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Other current liability: Gain positions	880	55
Other current liability: Loss positions	$ (1,831)	$ (3,210)

Financial Instruments - Effects

Financial Instruments - Effects of Derivative Instruments on Statements of Income (Details) - Cost of Goods Sold [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Commodity Contracts [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on the derivatives in designated and qualifying fair value hedges	$ 0	$ 0	$ 391	$ 0
Commodity Contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain on commodity contracts (nonqualifying)	(2,848)	(3,083)	5,579	(3,506)
Inventories [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on the derivatives in designated and qualifying fair value hedges	$ 0	$ 0	$ (385)	$ 0

Financial Instruments - Amounts

Financial Instruments - Amounts Recognized in and Reclassified from AOCI (Details) - Cash Flow Hedging [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax	$ 311	$ (518)	$ (441)	$ (1,175)
(Gain) Loss Reclassified from AOCI (Effective Portion), Net of Tax	(180)	386	(455)	1,360
Commodity Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax	305	(541)	(438)	(1,354)
Commodity Contracts [Member] | Cost of Goods Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) Loss Reclassified from AOCI (Effective Portion), Net of Tax	(180)	237	(455)	913
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax		0		0
Interest Rate Swap [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) Loss Reclassified from AOCI (Effective Portion), Net of Tax		149		447
Other [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) Gain Recognized in AOCI (Effective Portion), Net of Tax	6	23	(3)	179
(Gain) Loss Reclassified from AOCI (Effective Portion), Net of Tax	$ 0	$ 0	$ 0	$ 0

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		33 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018
Schedule of Equity Method Investments [Line Items]
Net loss	$ 5,007	$ 788	$ 22,867	$ 3,492
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	$ 2,500		$ 15,400
Gain from settlement with tax authority			$ 7,000
Second Unconsolidated Affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	50.00%		50.00%		50.00%
Cayan Ventures and Bahrain Mumtalakat Holding Company [Member]
Schedule of Equity Method Investments [Line Items]
Interest in the joint venture, ownership percentage	40.00%		40.00%		40.00%
Net loss	$ 500		$ 2,100
Cash invested to acquire joint venture interest					$ 4,500
Labor Claim [Member] | Tecumseh Products Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Contingency charge			$ 3,000

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. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 30, 2017
Balance sheet data [Abstract]
Current assets	$ 222,408		$ 222,408		$ 246,127
Noncurrent assets	112,547		112,547		139,200
Current liabilities	163,931		163,931		174,710
Noncurrent liabilities	60,112		60,112		$ 58,334
Income statement data [Abstract]
Net sales	131,827	$ 148,400	382,132	$ 407,300
Gross profit	18,140	21,500	41,989	56,700
Net loss	$ (5,007)	$ (788)	$ (22,867)	$ (3,492)

Benefit Plans (Details)

Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Pension Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	$ 22	$ 35	$ 66	$ 106
Interest cost	1,478	1,659	4,436	4,977
Expected return on plan assets	(2,290)	(2,184)	(6,869)	(6,552)
Amortization of net loss (gain)	293	536	877	1,608
Net periodic benefit (income) cost	(497)	46	(1,490)	139
Other Benefits [Member]
Components of net periodic benefit cost (income) [Abstract]
Service cost	59	54	175	163
Interest cost	147	147	441	442
Amortization of prior service credit	(226)	(225)	(677)	(676)
Amortization of net loss (gain)	14	(10)	43	(30)
Net periodic benefit (income) cost	$ (6)	$ (34)	$ (18)	$ (101)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	Jul. 13, 2018USD ($)	Jan. 31, 2018USD ($)unilateral_administrative_orders	Sep. 29, 2018USD ($)propertyImport_entry	Sep. 29, 2018potentially_responsible_party	Sep. 29, 2018smelter_site	Nov. 08, 2016USD ($)	Apr. 19, 2010
Loss Contingencies [Line Items]
Term of guarantees			1 year
Payments required to be made under guarantees, maximum			$ 8,500,000
United States Department of Commerce Antidumping Review [Member]
Loss Contingencies [Line Items]
Assignment of antidumping duty rate on U.S. imports by Company subsidiaries							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
Southeast Kansas Sites [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations				2	3
Environmental reserves			$ 5,600,000
Shasta Area Mine Sites [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Period of permit, implementation of Best Management Practices			10 years
Estimated remediation costs, term			30 years
Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Financial guarantee						$ 1,000,000
Lead Refinery Site [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs, term			19 years
Amount 2 other PRPs will pay to fund cleanup			$ 26,000,000
Number of surrounding properties | property			300
Lead Refinery NPL Site [Member]
Loss Contingencies [Line Items]
Environmental reserves		$ 4,500,000
Number of UAOs | unilateral_administrative_orders		2
Site contingency, total costs		$ 25,000,000
Site contingency, amount agreed upon to pay PRPs for past costs		$ 2,000,000
Mueller Copper Tube Products, Inc. [Member] | Operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs, term			8 years
Minimum [Member] | Shasta Area Mine Sites [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			$ 12,800,000
Minimum [Member] | Lead Refinery Site [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			1,800,000
Minimum [Member] | Mueller Copper Tube Products, Inc. [Member] | Operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			800,000
Maximum [Member] | Shasta Area Mine Sites [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			17,600,000
Maximum [Member] | Lead Refinery Site [Member] | Non operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			3,000,000
Maximum [Member] | Mueller Copper Tube Products, Inc. [Member] | Operating Properties [Member]
Loss Contingencies [Line Items]
Estimated remediation costs			$ 1,200,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 30, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	12.00%	27.00%	20.00%	29.00%
Adjustment to provisional tax calculation	$ (4.3)		$ (4.3)
Adjustment to provisional tax calculation, effect on diluted earnings per share (in dollars per share)	$ 0.07		$ 0.07
Provision for state income taxes, net of federal benefits	$ 0.7		$ 3.3	$ 1.7
Increase in valuation allowance	$ 1.5		$ 1.5
Increase in valuation allowance, effect on diluted earnings per share (in dollars per share)	$ 0.03		$ 0.03
Reduction for U.S. production activities		$ 0.6		2.4
Tax benefit of foreign adjustments		1.6	$ 0.8	4.6
Impact of investments in unconsolidated affiliates	$ 0.7		4.4	0.9
Global intangible low-taxed income expense			$ 0.8
Tax benefit of equity compensation deductions		$ 0.5		$ 2.2
One-time transition tax liability	8.6				$ 12.9
Provisional tax benefit	$ 12.1				$ 12.1

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Changes by Component (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		$ 536,028		$ 536,028
Total other comprehensive (loss) income, net	$ (5,395)		$ 6,080	(12,848)	$ 13,417
Reclassification of stranded effects of the Act		556
Ending balance	583,408			583,408
Total [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		(51,056)		(51,056)	(66,956)
Other comprehensive (loss) income before reclassifications				(12,220)	14,638
Amounts reclassified from AOCI				(237)	(2,059)
Total other comprehensive (loss) income, net				(12,457)	12,579
Reclassification of stranded effects of the Act				556
Ending balance	(62,957)		(54,377)	(62,957)	(54,377)
Cumulative Translation Adjustment [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		(38,163)		(38,163)	(49,965)
Other comprehensive (loss) income before reclassifications				(5,143)	18,209
Amounts reclassified from AOCI				0	(3,777)
Total other comprehensive (loss) income, net				(5,143)	14,432
Reclassification of stranded effects of the Act				0
Ending balance	(43,306)		(35,533)	(43,306)	(35,533)
Unrealized (Loss) Gain on Derivatives [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		847		847	(300)
Other comprehensive (loss) income before reclassifications				(441)	(1,175)
Amounts reclassified from AOCI				(455)	1,360
Total other comprehensive (loss) income, net				(896)	185
Reclassification of stranded effects of the Act				112
Ending balance	63		(115)	63	(115)
Pension/OPEB Liability Adjustment [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		(20,610)		(20,610)	(23,046)
Other comprehensive (loss) income before reclassifications				551	(1,309)
Amounts reclassified from AOCI				218	737
Total other comprehensive (loss) income, net				769	(572)
Reclassification of stranded effects of the Act				(1,018)
Ending balance	(20,859)		(23,618)	(20,859)	(23,618)
Unrealized Gain (Loss) on Equity Securities [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		0		0	380
Other comprehensive (loss) income before reclassifications				0	(1)
Amounts reclassified from AOCI				0	(379)
Total other comprehensive (loss) income, net				0	(380)
Reclassification of stranded effects of the Act				0
Ending balance	0		0	0	0
Attributable to Unconsolidated Affiliates [Member]
Changes in accumulated other comprehensive income [Roll Forward]
Beginning balance		$ 6,870		6,870	5,975
Other comprehensive (loss) income before reclassifications				(7,187)	(1,086)
Amounts reclassified from AOCI				0	0
Total other comprehensive (loss) income, net				(7,187)	(1,086)
Reclassification of stranded effects of the Act				1,462
Ending balance	$ 1,145		$ 4,889	$ 1,145	$ 4,889

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. 29, 2018	Sep. 30, 2017		Sep. 29, 2018	Sep. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 566,956	$ 471,262	[1]	$ 1,676,446	$ 1,484,000	[1]
Interest expense	6,746	5,237	[1]	18,728	14,210	[1]
Other income, net	(411)	380	[1]	(1,557)	(556)	[1]
Income tax (benefit) expense	3,373	8,716	[1]	23,179	33,295	[1]
Gain recognized upon sale of business	2,691	(140)	[1]	334	1,491	[1]
Net of tax and noncontrolling interests	(20,292)	(22,258)	[1]	(77,602)	(79,878)	[1]
Unrealized losses (gains) on derivatives [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	(204)	223		(550)	1,247
Interest expense	0	232		0	696
Income tax (benefit) expense	24	(69)		95	(583)
Net of tax and noncontrolling interests	(180)	386		(455)	1,360
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]
Other income, net	81	301		243	902
Income tax (benefit) expense	(9)	(55)		(25)	(165)
Net of tax and noncontrolling interests	72	246		218	737
Sale of available-for-sale securities [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net	0	0		0	(611)
Income tax (benefit) expense	0	0		0	232
Net of tax and noncontrolling interests	0	0		0	(379)
Gain recognized upon sale of business [Member] | Amount Reclassified from AOCI [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (benefit) expense	0	0		0	0
Gain recognized upon sale of business	0	0		0	(3,777)
Net of tax and noncontrolling interests	$ 0	$ 0		$ 0	$ (3,777)
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.

Noncontrolling Interests (Detai

Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	[1]	Sep. 29, 2018	Sep. 30, 2017	[1]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance as of December 30, 2017				$ 13,917
Dividends paid to noncontrolling interests				(592)
Net income attributable to noncontrolling interests	$ 571	$ 496		1,487	$ 1,164
Other comprehensive income attributable to noncontrolling interests, net of tax:
Foreign currency translation				(390)
Balance as of September 29, 2018	$ 14,422			$ 14,422
[1]	The Condensed Consolidated Statements of Income for the quarter and nine months ended September 30, 2017 have been adjusted to reflect the adoption of ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The components of net periodic benefit cost (income) other than the service cost component are included in other income (expense), net in the Condensed Consolidated Statements of Income. Refer to Note 1 for further discussion.