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v3.20.4

Restructuring and Other Items, net (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 27, 2020 USD ($) | Jun. 28, 2020 USD ($) Mill | Mar. 31, 2019 USD ($) Facility | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Restructuring Charges [Abstract] |  |  |  |  |  |
Asset write-down charges |  |  |  | $ 7.1 | $ 7.5 | $ 0.7
Severance and other employee costs |  |  |  | 0.3 | 5.7 | 1.8
Total restructuring and other items, net |  |  |  | 7.6 | 13.2 | 2.5
Restructuring Reserve [Roll Forward] |  |  |  |  |  |
Restructuring liability, beginning of period |  |  | $ 2.5 | 5.0 | 2.5 |
Additional provisions |  |  |  | 0.3 | 5.7 |
Cash payments |  |  |  | (1.6) | (3.2) |
Other |  |  |  | (0.1) | 0.0 |
Restructuring liability, ending of period |  |  |  | 3.6 | 5.0 | 2.5
Performance Materials [Member] |  |  |  |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Asset write-down charges |  |  |  | 0.0 | 4.2 | 0.0
Severance and other employee costs |  |  |  | 0.0 | 2.8 | 0.0
Specialty Minerals [Member] |  |  |  |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Asset write-down charges |  |  |  | 7.1 | 1.6 | 0.7
Severance and other employee costs |  |  |  | 0.3 | 0.9 | 0.0
Other |  |  |  | 0.2 | 0.0 | 0.0
Specialty Minerals [Member] | Paper PCC [Member] |  |  |  |  |  |
Restructuring and Other Items, Net [Abstract] |  |  |  |  |  |
Number of mills with lease terminations | Mill |  | 1 |  |  |  |
Number of facilities shut down | Facility |  |  | 1 |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Asset write-down charges | $ 1.1 | $ 6.0 |  |  |  |
Severance and other employee costs |  | $ 0.3 |  |  |  |
Refractories [Member] |  |  |  |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Severance and other employee costs |  |  |  | 0.0 | 0.8 | 0.0
Energy Services [Member] |  |  |  |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Asset write-down charges |  |  |  | 0.0 | 1.7 | 0.0
Severance and other employee costs |  |  |  | 0.0 | 0.1 | 1.8
Corporate [Member] |  |  |  |  |  |
Restructuring Charges [Abstract] |  |  |  |  |  |
Severance and other employee costs |  |  |  | $ 0.0 | $ 1.1 | $ 0.0
Verso Papers [Member] |  |  |  |  |  |
Restructuring and Other Items, Net [Abstract] |  |  |  |  |  |
Number of paper mills being idled indefinitely | Mill |  | 2 |  |  |  |

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