Commitments and Contingencies - Additional Information (Details)		1 Months Ended	9 Months Ended
	Jul. 13, 2018 USD ($)	Jan. 31, 2018 USD ($) unilateral_administrative_orders	Sep. 29, 2018 USD ($) property Import_entry	Sep. 29, 2018 potentially_responsible_party	Sep. 29, 2018 smelter_site	Nov. 08, 2016 USD ($)	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	$ 1,000,000.0
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