UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Cash flows from operating activities:
Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest	$ (5,325)	$ (713)
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Stock-based compensation	11,543	16,116
Depreciation and amortization	42,006	34,836
Operating Lease, Right-of-Use Asset, Amortization Expense	17,118	20,912
Gain (Loss) on Termination of Lease	(3,529)
Impairment and other losses	0	1,500
Deferred income taxes	(747)	(655)
Adjustment To Deferred Acquisition Consideration	6,657	154
Other, net	(2,060)	292
Changes in working capital:
Accounts receivable	(44,701)	(42,976)
Expenditures billable to clients	11,095	6,681
Other assets	(32,778)	(19,584)
Accounts payable	(35,287)	22,206
Accrued expenses and other liabilities	(19,075)	(63,856)
Advance billings	15,628	(6,124)
Increase (Decrease) in Operating Lease Liability	(20,558)	(21,660)
Deferred acquisition related payments	0	(250)
Net Cash Provided by (Used in) Operating Activities, Total	(60,013)	(53,121)
Cash flows from investing activities:
Capitalized software	(11,966)	(8,794)
Capital expenditures	(3,912)	(5,439)
Acquisitions, net of cash acquired	(1,090)	(11,673)
Other	(3,391)	(218)
Net Cash Provided by (Used in) Investing Activities, Total	(20,359)	(26,124)
Cash flows from financing activities:
Repayment of borrowings under revolving credit facility	(432,000)	(417,000)
Proceeds from borrowings under revolving credit facility	543,000	540,000
Shares repurchased and cancelled	(11,068)	(29,698)
Distributions to noncontrolling interests	(581)	(559)
Payment of deferred consideration	(16,103)	(1,657)
Net Cash Provided by (Used in) Financing Activities, Total	83,248	91,086
Effect of exchange rate changes on cash and cash equivalents	3,438	(1,754)
Net increase in cash and cash equivalents	6,314	10,087
Cash and cash equivalents at beginning of period	131,339	119,737
Cash and cash equivalents at end of period	137,653	129,824
Supplemental Cash Flow Information:
Cash income taxes paid	7,908	8,535
Cash interest paid	37,738	35,253
Non-cash investing and financing activities:
Acquisitions of business	0	6,139
Noncash or Part Noncash Acquisition, Noncontrolling Interest Acquired	0	10,167
Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Issued	$ 0	$ 341