SHAREHOLDERS EQUITY - Stock based compensation - Share Awards (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Stock surrendered (in shares)	7,835	6,313	7,835	6,313
Stock surrendered to cover employee withholding taxes	$ 0.1	$ 0.2	$ 0.1	$ 0.2
Time Vesting Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year			184,369
Granted (in shares)			71,127
Vested (in shares)			(23,281)
Forfeited (in shares)			(16,318)
Outstanding at end of year	215,897		215,897
Stock issued (in shares)	15,446	16,969	15,446	16,969
Financial Performance Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year			15,932
Granted (in shares)			59,536
Forfeited (in shares)			(4,603)
Outstanding at end of year	70,865		70,865
Market Performance Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding at beginning of year			17,258
Forfeited (in shares)			(1,512)
Outstanding at end of year	15,746		15,746