EARNINGS PER COMMON SHARE - Anti-dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	190,911	638,902	228,532	618,787
Stock options
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	139,639	419,197	186,462	419,197
Time Vesting Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities		82,600	1,327	87,304
Financial Performance Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	40,745	116,051	30,216	70,769
Restricted Stock Awards
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	10,527	21,054	10,527	41,517