STOCK-BASED COMPENSATION - Stock Option Award Activity (Details) - Common stock options	3 Months Ended
	Mar. 31, 2021 shares
Outstanding
Outstanding at the beginning of the year (in shares)	1,140,975
Granted (in shares)	5,000
Exercised (in shares)	(104,465)
Cancelled or expired (in shares)	(5,152)
Outstanding at the end of the reporting period (in shares)	1,036,358
Exercisable
Exercisable at the beginning of the year (in shares)	955,302
Vested (in shares)	20,817
Exercised (in shares)	(104,465)
Cancelled or expired (in shares)	0
Exercisable at the end of the reporting period (in shares)	871,654