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Stock-Based Compensation | 9 Months Ended
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Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Stock-Based Compensation | STOCK-BASED COMPENSATION We recognize the cost of employee compensation received in the form of equity instruments based on the grant date fair value of those awards. The table below sets forth the total amount of stock-based compensation expense for the nine months and quarter ended September 30, 2017 and 2016.
|  | Quarter Ended September 30, |  | Nine Months Ended September 30,
|  | 2017 |  | 2016 |  | 2017 |  | 2016
|  | (Thousands of dollars)
Stock-based compensation expense: |  |  |  |  |  |
Time-based restricted stock units |  | $ | 582 |  |  | $ | 631 |  |  | $ | 1,678 |  |  | $ | 1,847 |
Performance-based restricted stock units |  | 689 |  |  | 823 |  |  | 1,396 |  |  | 2,502 |
Total stock-based compensation expense |  | $ | 1,271 |  |  | $ | 1,454 |  |  | $ | 3,074 |  |  | $ | 4,349 |
During the quarter and nine months ended September 30, 2017, 26,296 and 472,913 time-based restricted units, respectively, and 4,646 and 371,045 performance-based restricted units were awarded to managerial employees. During the quarter and nine months ended September 30, 2016, 10,992 and 25,280 time-based restricted units, respectively, and 2,318 and 310,481 performance-based restricted units were awarded to managerial employees, respectively.

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- Definition The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -URI http://asc.fasb.org/topic&trid=2228938 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 50 -URI http://asc.fasb.org/subtopic&trid=2208855 + Details
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