MARKETABLE SECURITIES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable securities—cost	$ 15,801		$ 15,801		$ 17,866
Unrealized gains	2,997		2,997		3,413
Unrealized losses	(266)		(266)		(34)
Net unrealized gain	2,731		2,731		3,379
Marketable securities—fair value	18,532		18,532		$ 21,245
Proceeds from sale of marketable securities	4,801	$ 6,631	20,156	$ 16,695
Gross realized gains from sale of marketable securities	113	335	706	804
Gross realized losses from sale of marketable securities	$ 512	$ 61	$ 3,255	$ 265