STOCK-BASED COMPENSATION - ACTIVITY OF STOCK OPTIONS (Details) - LTIP - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Stock Options
Outstanding at beginning of period (shares)	132,809
Granted (shares)	0
Exercised (shares)	0
Forfeited (shares)	(25,470)
Outstanding at end of period (shares)	107,339	132,809
Number of options outstanding and exercisable (shares)	36,674
Weighted- Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 34.36
Granted (in dollars per share)	0.00
Exercised (in dollars per share)	0.00
Forfeited (in dollars per share)	34.36
Outstanding at end of period (in dollars per share)	34.36	$ 34.36
Number of options outstanding and exercisable (in dollars per share)	$ 34.36
Weighted-Average Remaining Contractual Term (in years)
Weighted Average Remaining Contractual Term (in years)	7 years 11 months 16 days	6 years 8 months 12 days
Weighted-Average Remaining Contractual Life (in years)	7 years 8 months 27 days
Outstanding, Aggregate Intrinsic Value	$ 0	$ 0