SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) customer shares	Dec. 31, 2022 USD ($) customer shares	Dec. 31, 2021 USD ($) shares
Summary Of Significant Accounting Policies [Line Items]
Net gain (loss) on foreign currency transaction	$ (1,929)	$ 3,859	$ 2,779
Sales rebates	12,100	7,900	$ 7,200
Performance obligations remaining to be performed	$ 2,900,000	$ 2,700,000
Number of customers accounted for more than 10% of accounts receivable | customer	0	0
Government assistance, amount	$ 15,500	$ 15,400
Government Assistance, Statement of Income or Comprehensive Income [Extensible Enumeration]	Direct operating costs, Selling, general and administrative
Prepaid Expenses and Other Current Assets
Summary Of Significant Accounting Policies [Line Items]
Government assistance, amount	$ 9,500	11,300
Other Assets
Summary Of Significant Accounting Policies [Line Items]
Government assistance, amount	$ 12,200	$ 7,100
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of finite-lived intangible assets	15 years
Maximum | 2016 Incentive Award Plan
Summary Of Significant Accounting Policies [Line Items]
Share-based compensation option terms	10 years
Maximum | Computer Hardware Software Phone and Medical Imaging Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	5 years
Maximum | Furniture and Fixtures and Other Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	7 years
Maximum | Buildings
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	40 years
Maximum | Computer Software Developed Costs
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Minimum | Computer Hardware Software Phone and Medical Imaging Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Minimum | Furniture and Fixtures and Other Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	5 years
Minimum | Buildings
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	30 years
Stock options
Summary Of Significant Accounting Policies [Line Items]
Anti-dilutive securities excluded from computation of diluted EPS (in shares) | shares	0	9	9
Selling, general, and administrative
Summary Of Significant Accounting Policies [Line Items]
Advertisement expenses	$ 1,500	$ 1,300	$ 1,200