CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 228,297	$ 344,060
Adjustments to reconcile net income to net cash provided by operating activities:
Allowance for credit losses	3,529	4,316
Depreciation	25,229	22,907
Amortization of cloud computing implementation costs	16,351	13,804
Amortization of intangible assets	1,442	833
Realized and unrealized (gains) losses from investments held in employee deferred compensation trusts	(51,843)	98,233
Stock-based compensation	30,887	29,593
Deferred income taxes	(3,583)	6,421
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable	45,943	(129,983)
Capitalized cloud computing implementation costs	(20,184)	(19,540)
Accounts payable and accrued expenses	(21,882)	(8,374)
Accrued payroll and benefit costs	(26,539)	15,848
Employee deferred compensation plan obligations	56,418	(94,957)
Income taxes payable	67,672	21,516
Other assets and liabilities, net	(5,134)	(2,599)
Net cash flows provided by operating activities	346,603	302,078
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(19,093)	(35,275)
Investments in employee deferred compensation trusts	(81,714)	(45,061)
Proceeds from employee deferred compensation trust redemptions	24,053	25,140
Payments for acquisition	(1,035)	0
Net cash flows used in investing activities	(77,789)	(55,196)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repurchases of common stock	(104,664)	(160,610)
Dividends paid	(104,680)	(96,229)
Net cash flows used in financing activities	(209,344)	(256,839)
Effect of exchange rate fluctuations	4,667	(18,135)
Change in cash and cash equivalents	64,137	(28,092)
Cash and cash equivalents at beginning of period	658,626	619,001
Cash and cash equivalents at end of period	722,763	590,909
Non-cash items:
Repurchases of common stock awaiting settlement	3,684	11,296
Fund exchanges within employee deferred compensation trusts	70,608	66,645
Contingent consideration related to acquisition	$ 350	$ 0