ACCOUNTS RECEIVABLE (SCHEDULE OF CHANGE IN ALLOWANCE) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
ACCOUNTS RECEIVABLE AND SIGNIFICANT CLIENTS [Abstract]
Balance, beginning balance	$ 5,940,000	$ 5,795,000	$ 5,067,000	$ 5,452,000
Provision for credit losses	(189,000)	44,000	(34,000)	563,000
Uncollectible receivables written-off recoveries	302,000	(806,000)	41,000	(939,000)
Effect of foreign currency	(7,000)	24,000	(16,000)	(19,000)
Acquisition credit losses			988,000
Balance, ending balance	$ 6,046,000	$ 5,057,000	$ 6,046,000	$ 5,057,000