SHAREHOLDERS' EQUITY - Employee Stock Purchase Plan (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Class of Stock [Line Items]
Espp Shares Market Value	85.00%
Employee stock ownership plan (ESOP) (in shares)	1,000
ESPP share discount	15.00%
Non-cash compensation expense recognized	$ 1,780	$ 3,573
Employee Stock Purchase Plan
Class of Stock [Line Items]
Number of shares purchased (in shares)	166	85
Non-cash compensation expense recognized	$ 43	$ 67