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v3.20.2

Segment Information (Revenue and Long-Lived Assets by Geographical Areas) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues | $ 265.3 | $ 228.5 | $ 257.7 | $ 212.6 | $ 266.9 | $ 274.3 | $ 234.0 | $ 192.8 | $ 964.1 | $ 968.0 | $ 916.0
Intangible Assets, Net (Including Goodwill) | 508.7 |  |  |  | 529.4 |  |  |  | 508.7 | 529.4 |
Total assets | 1,395.0 |  |  |  | 1,337.3 |  |  |  | $ 1,395.0 | 1,337.3 |
Document Period End Date |  |  |  |  |  |  |  |  | Sep. 30, 2020 |  |
Property, plant and equipment, net | 253.8 |  |  |  | 217.1 |  |  |  | $ 253.8 | 217.1 |
United States |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, net | 234.7 |  |  |  | 201.3 |  |  |  | 234.7 | 201.3 |
Canada |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, net | 12.8 |  |  |  | 9.7 |  |  |  | 12.8 | 9.7 |
Other |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Property, plant and equipment, net | 6.3 |  |  |  | 6.1 |  |  |  | 6.3 | 6.1 |
Mueller Co. [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 885.5 | 871.0 | 818.8
Intangible Assets, Net (Including Goodwill) | 490.8 |  |  |  | 508.2 |  |  |  | 490.8 | 508.2 |
Total assets | 1,149.8 |  |  |  | 1,107.8 |  |  |  | 1,149.8 | 1,107.8 |
Mueller Co. [Member] | Central Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 222.2 | 214.2 |
Mueller Co. [Member] | United States |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 788.9 | 772.8 |
Mueller Co. [Member] | Canada |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 65.5 | 69.0 |
Mueller Co. [Member] | Northeast Region [Member] [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 187.5 | 183.1 |
Mueller Co. [Member] | Southeast Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 162.3 | 162.7 |
Mueller Co. [Member] | Western Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 216.9 | 212.8 |
Mueller Co. [Member] | Other International Locations [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 31.1 | 29.2 |
Mueller Technologies [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 78.6 | 97.0 | 97.2
Intangible Assets, Net (Including Goodwill) | 17.9 |  |  |  | 21.2 |  |  |  | 17.9 | 21.2 |
Total assets | 93.2 |  |  |  | 100.3 |  |  |  | 93.2 | 100.3 |
Mueller Technologies [Member] | Central Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 18.7 | 27.8 |
Mueller Technologies [Member] | United States |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 74.1 | 92.0 |
Mueller Technologies [Member] | Northeast Region [Member] [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 19.7 | 20.4 |
Mueller Technologies [Member] | Southeast Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 22.1 | 33.5 |
Mueller Technologies [Member] | Western Region [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 13.6 | 10.3 |
Mueller Technologies [Member] | Other International Locations [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 4.5 | 5.0 |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Ferguson Enterprises |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Accounts and Other Receivables, Net, Current | 26.1 |  |  |  | $ 25.8 |  |  |  | 26.1 | $ 25.8 |
Customer Concentration Risk [Member] | Accounts Receivable [Member] | HDS IP Holdings, LLC [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
Accounts and Other Receivables, Net, Current | $ 37.1 |  |  |  |  |  |  |  | $ 37.1 |  | $ 31.9
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | Major Customers, Group One |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 53.00% | 53.00% | 54.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | Major Customers, Group Two |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 34.00% | 34.00% | 34.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | Ferguson Enterprises |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 17.00% | 18.00% | 19.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | Ferguson Enterprises | Mueller Co. [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 16.00% | 17.00% | 18.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | Ferguson Enterprises | Mueller Technologies [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 22.00% | 30.00% | 28.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | HDS IP Holdings, LLC [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 17.00% | 16.00% | 15.00%
Customer Concentration Risk [Member] | Sales Revenue, Goods, Gross [Member] | HDS IP Holdings, LLC [Member] | Mueller Co. [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues from External Customers and Long-Lived Assets [Line Items] |  |  |  |  |  |  |  |  |  |  |
10 largest customers |  |  |  |  |  |  |  |  | 19.00% | 18.00% | 17.00%

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