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v3.20.4

Employee Benefits - Supplemental Bonus Plan (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | $ 53.0 | $ 42.1 | $ 45.0
Master Plan |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | 21.2 | 22.7 | 28.1
Other defined contribution plans |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | 6.9 | 9.6 | 9.4
ESOP |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans |  |  | 1.9
Reliance Deferred Compensation Plan |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | (0.3) | 5.0 | 0.9
SERPs |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | 10.5 | 3.3 | 2.9
Defined Benefit Plans |  |  |
Contributions to Company Sponsored Retirement Plans |  |  |
Company's expense for Reliance-sponsored retirement plans | $ 14.7 | $ 1.5 | $ 1.8

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