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Incentive Plans (Tables) | 3 Months Ended
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Mar. 31, 2021
Share-based Payment Arrangement [Abstract] |
Share-Based Plans, Amounts Recognized in the Financial Statements | Amounts recognized in the financial statements with respect to share-based plans are shown in the following table:
| Three Months Ended March 31,
(Thousands of dollars) | 2021 |  | 2020
Compensation charged against income before tax benefit | $ | 8,196 |  |  | 553 |
Related income tax (expense) benefit recognized in income | 1,165 |  |  | (592) |

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- Definition Tabular disclosure of cost recognized for award under share-based payment arrangement by plan. Includes, but is not limited to, related tax benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
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