Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Assets, Current [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 96,929	$ 172,747
Accounts Receivable, after Allowance for Credit Loss, Current	430,092	394,868
Prepaid Expense and Other Assets, Current	105,355	95,064
Income Taxes Receivable, Current	20,690	18,524
Total current assets	653,066	681,203
Long-term assets
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	146,358	191,003
Asset, Held-for-Sale, Not Part of Disposal Group, Other	29,640	0
Operating lease assets	100,263	121,574
Goodwill	575,096	808,988
Deferred tax assets, net	12,398	38,151
Other intangible assets, net	173,227	198,433
Income Taxes Receivable, Noncurrent	34,469	44,673
Other long-term assets	101,773	101,573
Total long-term assets	1,173,224	1,504,395
Total assets	1,826,290	2,185,598
Liabilities, Current [Abstract]
Accounts payable	82,259	96,577
Employee-related Liabilities, Current	121,255	146,184
Other accrued expenses	26,116	32,217
Accrued Income Taxes, Current	292	4,909
Deferred revenue	70,834	81,171
Current operating lease liabilities	35,217	38,271
Other Liabilities, Current	2,677	3,698
Total current liabilities	338,650	403,027
Liabilities, Noncurrent [Abstract]
Long-Term Line of Credit, Noncurrent	1,025,000	995,000
Deferred tax liabilities, net	15,011	3,137
Accrued Income Taxes, Noncurrent	0	0
Non-current operating lease liabilities	79,909	96,809
Other long-term liabilities	72,586	72,083
Total long-term liabilities	1,192,506	1,167,029
Total liabilities	1,531,156	1,570,056
Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Preferred Stock, Value, Issued	0	0
Common Stock, Value, Outstanding	477	474
Additional Paid in Capital	416,813	407,415
Treasury stock at cost: 34,328,331 and 34,625,053 shares as of September 30, 2024 and December 31, 2023, respectively	(584,904)	(589,807)
Accumulated other comprehensive income (loss)	(99,697)	(89,876)
Retained Earnings (Accumulated Deficit)	544,616	870,429
Noncontrolling interest	17,829	16,907
Total stockholders' equity	295,134	615,542
Total liabilities and stockholders' equity and mezzanine equity	$ 1,826,290	$ 2,185,598