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v3.19.3.a.u2

Summary of Significant Accounting Policies, Narrative (Details) $ in Millions | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2019 USD ($) segment | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Jan. 01, 2019 USD ($) | Jan. 01, 2018 USD ($) | [1] | Jan. 01, 2017 USD ($)
Accounting policies additional disclosures |  |  |  |  |  |
Effect of LIFO Inventory Liquidation on Income | $ 3.6 |  |  |  |  |
Number of operating segments | segment | 1 |  |  |  |  |
Advertising costs | $ 0.4 | $ 0.3 | $ 0.7 |  |  |
Research and development costs | 10.5 | 9.8 | 10.0 |  |  |
Excess of current cost over the stated LIFO value of inventory | 11.9 | 31.7 |  |  |  |
Non-cash asset impairment charges | 26.1 | 1.4 | $ 19.2 |  |  |
Undiscounted workers' compensation liabilities | $ 29.2 | $ 27.6 |  |  |  |
Discount rate used in estimating liabilities for worker compensation claims | 1.75% | 3.00% |  |  |  |
Accrued employee healthcare benefits | $ 3.5 | $ 3.6 |  |  |  |
Retained earnings | 172.8 | 150.2 |  |  |  |
Operating lease assets | 25.8 | 0.0 |  |  |  |
Operating Lease, Liability, Current | 3.9 |  |  |  |  |
Long-term portion of operating lease liabilities | $ 25.2 | $ 0.0 |  |  |  |
Cumulative-effect adjustment |  |  |  |  | $ 10.3 | $ 0.3
Minimum |  |  |  |  |  |
Accounting policies additional disclosures |  |  |  |  |  |
Period over which accounts receivable is due, days | 30 days |  |  |  |  |
Number of days in maturity for debt investment securities to be classified as short-term investments | 90 days |  |  |  |  |
Maximum |  |  |  |  |  |
Accounting policies additional disclosures |  |  |  |  |  |
Period over which accounts receivable is due, days | 90 days |  |  |  |  |
Number of days to maturity for debt investment securities to be classified as cash and cash equivalents | 90 days |  |  |  |  |
Accounting Standards Update 2016-02 |  |  |  |  |  |
Accounting policies additional disclosures |  |  |  |  |  |
Operating lease assets |  |  |  | $ 29.0 |  |
Operating Lease, Liability, Current |  |  |  | 4.1 |  |
Long-term portion of operating lease liabilities |  |  |  | 27.4 |  |
Cumulative-effect adjustment |  |  |  | $ 0.0 |  |
[1] | Cumulative-effect adjustment relates to our adoption of ASC 606 and ASU 2016-01 (each as defined in Note 1).

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