ACCOUNTS RECEIVABLE (SCHEDULE OF CHANGE IN ALLOWANCE) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
ACCOUNTS RECEIVABLE AND SIGNIFICANT CLIENTS [Abstract]
Balance, beginning of year	$ 5,067	$ 5,452
Provision for credit losses	21	162
Uncollectible receivables written-off	(83)	(208)
Effect of foreign currency	(8)	(4)
Balance, end of year	$ 4,997	$ 5,402