EARNINGS PER COMMON SHARE - Anti-dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	638,902	670,714	618,787	732,226
Stock options
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	419,197	423,197	419,197	438,364
Time Vesting Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	82,600	130,821	87,304	163,141
Financial Performance Units
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	116,051	55,028	70,769	47,008
Restricted Stock Awards
EARNINGS PER COMMON SHARE
Total potentially dilutive securities	21,054	61,668	41,517	83,713