STOCK-BASED COMPENSATION - Summary of Stock options exercised, restricted stock vested, shares withheld and shares issued (Details) - USD ($)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Number of Shares
Stock compensation expense	$ 557,000	$ 545,000
Unrecognized compensation expense	$ 5,300,000
Weighted average period	2 years 6 months
Stock options
Number of Shares
Stock Options, Exercised/Vested	1,524	10,844
Stock Options, Shares Issued	1,524	10,844
Non-performance based restricted stock
Number of Shares
Restricted Stock, Exercised/Vested	6,450	300
Restricted Stock, Shares withheld	(1,218)	(89)
Restricted Stock, Shares Issued	$ 5,232	$ 211

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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