MARKETABLE SECURITIES - Sale of Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Sale Of Marketable Securities [Abstract]
Proceeds from sales	$ 3,957	$ 9,457	$ 3,957	$ 9,457
Gross gains	0	0	0	0
Gross losses	$ (22)	$ (51)	$ (22)	$ (51)