EARNINGS PER COMMON SHARE - Anti-dilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	168,374	649,672	247,344	608,731
Stock options
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	141,639	419,197	209,874	419,197
Time Vesting Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities		92,388	1,991	89,656
Financial Performance Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	26,735	96,257	24,952	48,129
Restricted Stock Awards
EARNINGS PER COMMON SHARE
Total potentially dilutive securities		41,830	10,527	51,749