GOODWILL AND OTHER INTANGIBLES - Schedule of Intangibles (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Goodwill and Other Intangible Assets [Line Items]
Cost	$ 136,550	$ 136,493
Accumulated Amortization	(128,601)	(125,605)
Net Book Value	7,949	10,888
Client-related
Goodwill and Other Intangible Assets [Line Items]
Cost	63,086	63,076
Accumulated Amortization	(59,661)	(58,623)
Net Book Value	3,425	4,453
Technology
Goodwill and Other Intangible Assets [Line Items]
Cost	68,103	68,056
Accumulated Amortization	(63,579)	(61,621)
Net Book Value	4,524	6,435
Other
Goodwill and Other Intangible Assets [Line Items]
Cost	5,361	5,361
Accumulated Amortization	(5,361)	(5,361)
Net Book Value	$ 0	$ 0
Minimum | Client-related
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	4 years	4 years
Minimum | Technology
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	2 years	2 years
Minimum | Other
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	1 year	1 year
Maximum | Client-related
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	10 years	10 years
Maximum | Technology
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	10 years	10 years
Maximum | Other
Goodwill and Other Intangible Assets [Line Items]
Useful Lives	5 years	5 years