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v3.20.1

Commitments and Contingencies (Details) |  | 1 Months Ended | 3 Months Ended | 12 Months Ended | 18 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jul. 13, 2018 USD ($) | Jan. 31, 2018 USD ($) unilateral_administrative_order potentially_responsible_party | Nov. 27, 2015 USD ($) | Mar. 28, 2020 USD ($) property | Oct. 31, 2008 Import_entry | Jun. 29, 2019 USD ($) | Mar. 28, 2020 potentially_responsible_party | Mar. 28, 2020 smelter_site | Feb. 12, 2020 USD ($) | Nov. 08, 2016 USD ($) | Apr. 19, 2010
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Term of guarantees |  |  |  | 1 year |  |  |  |  |  |  |
Payments required to be made under guarantees, maximum |  |  |  | $ 11,400,000 |  |  |  |  |  |  |
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 |  |  |  |  |  |  | 2 | 3 |  |  |
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 |  |  |  |  |  |  |

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