STOCK OPTIONS - Schedule of Nonvested Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Outstanding at beginning of year (in shares)	331,560	334,400	334,400
Granted (in shares)	35,000	90,000
Vested (in shares)	(54,340)	(44,940)
Forfeited (in shares)	(23,600)	(9,400)
Balance (in shares)	288,620	370,060	331,560	334,400
Weighted-Average Exercise Price
Outstanding at beginning of year (in USD per share)	$ 27.74	$ 25.72	$ 25.72
Granted (in USD per share)	29.85	32.59
Vested (in USD per share)	28.10	26.19
Forfeited (in USD per share)	33.03	29.38
Balance (in USD per share)	$ 27.78	$ 27.39	$ 27.74	$ 25.72
Weighted-Average Remaining Contractual Life in Years
Outstanding	7 years 1 month 28 days	7 years 8 months 19 days	7 years 9 months 7 days	7 years 10 months 28 days
Granted	9 years 7 months 9 days	9 years 8 months 19 days
Vested	7 years 5 months 23 days	8 years 14 days
Forfeited	9 years 2 months 4 days	7 years 2 months 12 days
Aggregate Intrinsic Value
Outstanding	$ 975	$ 1,673	$ 1,673
Granted	26	0
Vested	172	199
Forfeited	46	81
Outstanding	$ 949	$ 1,297	$ 975	$ 1,673