SHAREHOLDERS’ EQUITY (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Summary of activities in common stock

The following table details activity in our common stock:

	Years Ended December 31,
	2020			2019			2018
	Shares	Amount		Shares	Amount		Shares	Amount
Stock option exercises	1,174	$	124,363	999	$	96,908	1,126	$	74,907
Purchases of common stock	(59)	(15,484)		(72)	(14,289)		(781)	(150,050)
Employee stock plan purchases	40	10,912		53	9,576		45	8,051
Restricted stock units vested, net of withheld shares upon award settlement	76	(12,923)		53	(5,361)		—	—