Commitments and Contingencies (Details)		1 Months Ended		9 Months Ended	12 Months Ended	33 Months Ended
	Jul. 13, 2018 USD ($)	Jan. 31, 2018 USD ($) unilateral_administrative_order potentially_responsible_party	Nov. 27, 2015 USD ($)	Sep. 26, 2020 USD ($) property smelter_site	Oct. 31, 2008 Import_entry	Sep. 26, 2020 USD ($) smelter_site	Sep. 26, 2020 potentially_responsible_party	Sep. 26, 2020 USD ($)	Feb. 12, 2020 USD ($)	Nov. 08, 2016 USD ($)	Apr. 19, 2010
Loss Contingencies [Line Items]
Term of guarantees				1 year
Payments required to be made under guarantees, maximum								$ 19,500,000
United States Department of Commerce Antidumping Review [Member]
Loss Contingencies [Line Items]
Assignment of antidumping duty rate on U.S. imports by Company subsidiaries (as a percent)											48.33%
Payment for interest and duties			$ 3,000,000.0
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
Deepwater Horizon Economic and Property Damage Claim [Member]
Loss Contingencies [Line Items]
Amount awarded to the Company									$ 21,900,000
Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Financial guarantee										$ 1,000,000.0
Lead Refinery NPL Site [Member]
Loss Contingencies [Line Items]
Environmental reserves		$ 4,500,000
Number of UAOs | unilateral_administrative_order		2
Number of PRPs | potentially_responsible_party		4
Site contingency, total costs		$ 25,000,000.0
Site contingency, amount agreed upon to pay PRPs for past costs		2,000,000.0
Site contingency, additional reimbursement of past costs		$ 700,000
Site contingency, amount paid to date for reimbursement of costs						$ 400,000
Contingency charge				$ 7,100,000
Non operating Properties [Member] | Southeast Kansas Sites [Member]
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations				3		3	2
Environmental reserves								$ 5,600,000
Non operating Properties [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Period of permit, implementation of Best Management Practices				10 years
Estimated remediation costs, term				30 years
Non operating Properties [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Number of parties involved in settlement negotiations | potentially_responsible_party							2
Estimated remediation costs, term				17 years
Amount other PRPs will pay to fund cleanup				$ 26,000,000.0
Number of surrounding properties | property				300
Non operating Properties [Member] | Minimum [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 12,700,000
Non operating Properties [Member] | Minimum [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				1,800,000
Non operating Properties [Member] | Maximum [Member] | Shasta Area Mine Sites [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				17,700,000
Non operating Properties [Member] | Maximum [Member] | Lead Refinery Site [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 2,300,000
Operating Properties [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs, term				6 years
Operating Properties [Member] | Minimum [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 600,000
Operating Properties [Member] | Maximum [Member] | Mueller Copper Tube Products, Inc. [Member]
Loss Contingencies [Line Items]
Estimated remediation costs				$ 900,000