STOCK OPTIONS - Schedule of 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)	537,872	469,044	469,044
Granted (in shares)	35,000	90,000
Exercised (in shares)	(22,172)	(6,000)
Forfeited (in shares)	(26,400)	(11,800)
Balance (in shares)	524,300	541,244	537,872	469,044
Exercisable
Outstanding (in shares)	235,680	171,184
Weighted-average exercise price (in USD per share)	$ 25.22	$ 24.29
Weighted-average remaining contractual life in years	5 years 5 months 1 day	5 years 9 months 21 days
Aggregate intrinsic value	$ 1,307	$ 1,024
Weighted-Average Exercise Price
Outstanding at beginning of year (in USD per share)	$ 26.49	$ 25.11	$ 25.11
Granted (in USD per share)	29.85	32.59
Exercised (in USD per share)	24.93	23.33
Forfeited (in USD per share)	29.53	23.41
Balance (in USD per share)	$ 26.63	$ 26.41	$ 26.49	$ 25.11
Weighted-Average Remaining Contractual Life in Years
Outstanding	6 years 4 months 17 days	7 years 1 month 13 days	6 years 11 months 15 days	7 years 3 months 25 days
Granted	9 years 7 months 9 days	9 years 8 months 19 days
Exercised	5 years 3 months 14 days	5 years 11 months 23 days
Forfeited	8 years 2 months 12 days	5 years 8 months 26 days
Aggregate Intrinsic Value
Outstanding	$ 2,088	$ 2,623	$ 2,623
Granted	26	0
Exercised	125	41
Forfeited	46	81
Outstanding	$ 2,255	$ 2,320	$ 2,088	$ 2,623