EARNINGS PER COMMON SHARE - Anti-dilutive Securities (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
EARNINGS (LOSS) PER COMMON SHARE
Total potentially dilutive securities	670,714	697,084	732,226	474,461
Stock Options
EARNINGS (LOSS) PER COMMON SHARE
Total potentially dilutive securities	423,197	467,947	438,364	296,949
Time Vesting Units
EARNINGS (LOSS) PER COMMON SHARE
Total potentially dilutive securities	130,821	168,962	163,141	157,454
Financial Performance Units
EARNINGS (LOSS) PER COMMON SHARE
Total potentially dilutive securities	55,028	16,345	47,008	5,448
Restricted Stock Awards
EARNINGS (LOSS) PER COMMON SHARE
Total potentially dilutive securities	61,668	43,830	83,713	14,610