Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Plans, Amounts Recognized

Amounts recognized in the financial statements with respect to share-based plans are shown in the following table:

	Six Months Ended June 30,
(Thousands of dollars)	2019		2018
Compensation charged against income before tax benefit	$	30,003	18,970
Related income tax benefit recognized in income	4,387		2,463