Stock-Based Compensation

9 Months Ended

Sep. 30, 2016

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

Stock-Based Compensation

7. 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 quarters ended September 30, 2016 and 2015.

	Quarter Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
	(Thousands of dollars)
Stock-based compensation expense:
Time-based restricted stock units	$	631	$	619	$	1,847	$	1,827
Performance-based restricted stock units		823		1,081		2,502		3,232
Total stock-based compensation expense	$	1,454	$	1,700	$	4,349	$	5,059

During the quarter and nine months ended September 30, 2016, 10,992 and 25,280 time-based restricted stock units were awarded to managerial employees, respectively.

During the quarter and nine months ended September 30, 2016, 2,318 and 310,481 performance-based restricted stock units were awarded to managerial employees, respectively.

During the quarter and nine months ended September 30, 2015, 13,545 and 33,593 time-based restricted stock units were awarded to managerial employees, respectively.

During the quarter and nine months ended September 30, 2015, 765 and 152,331 performance-based restricted stock units were awarded to managerial employees, respectively.