STOCK OPTIONS - Schedule of Nonvested Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 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)	23,000	59,000
Vested (in shares)	(37,940)	(33,740)
Forfeited (in shares)	(16,400)	(1,600)
Balance (in shares)	300,220	358,060	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)	29.77	32.66
Vested (in USD per share)	27.28	25.30
Forfeited (in USD per share)	30.49	23.00
Balance (in USD per share)	$ 27.89	$ 26.91	$ 27.74	$ 25.72
Weighted-Average Remaining Contractual Life in Years
Outstanding	7 years 4 months 17 days	7 years 9 months	7 years 9 months 7 days	7 years 10 months 28 days
Granted	9 years 8 months 8 days	9 years 10 months 2 days
Vested	7 years 6 months 14 days	8 years 1 month 9 days
Forfeited	8 years 8 months 15 days	6 years 9 months 18 days
Aggregate Intrinsic Value
Outstanding	$ 975	$ 1,673	$ 1,673
Granted	32	24
Vested	163	258
Forfeited	52	16
Outstanding	$ 1,087	$ 2,165	$ 975	$ 1,673