SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Balances Related to Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 117,400	$ 115,372
Less accumulated depreciation	(101,364)	(96,937)
Property and equipment, net	16,026	18,435
Building and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	9,700	9,100
Equipment and Furniture [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	56,900	54,700
Finance Leases [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,100	4,500
Property and equipment, net	2,300	1,700
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 46,700	$ 47,000