Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 344,060	$ 259,811
Adjustments to reconcile net income to net cash provided by operating activities:
Allowance for credit losses	4,316	4,733
Depreciation	22,907	27,715
Amortization of cloud computing implementation costs	13,804	13,353
Amortization of intangible assets	833	1,152
Realized and unrealized (gains) losses from investments held in employee deferred compensation trusts	98,233	(36,949)
Stock-based compensation	29,593	28,085
Deferred income taxes	6,421	(5,524)
Changes in operating assets and liabilities:
Accounts receivable	(129,983)	(201,602)
Capitalized cloud computing implementation costs	(19,540)	(16,236)
Accounts payable and accrued expenses	(8,374)	17,138
Accrued payroll and benefit costs	15,848	68,340
Employee deferred compensation plan obligations	(94,957)	46,236
Income taxes payable	21,516	22,110
Other assets and liabilities, net	(2,599)	5,110
Net cash flows provided by operating activities	302,078	233,472
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(35,275)	(16,114)
Investments in employee deferred compensation trusts	(45,061)	(42,423)
Proceeds from employee deferred compensation trust redemptions	25,140	27,424
Net cash flows used in investing activities	(55,196)	(31,113)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of notes payable	0	(117)
Repurchases of common stock	(160,610)	(145,314)
Dividends paid	(96,229)	(86,479)
Net cash flows used in financing activities	(256,839)	(231,910)
Effect of exchange rate fluctuations	(18,135)	(2,070)
Change in cash and cash equivalents	(28,092)	(31,621)
Cash and cash equivalents at beginning of period	619,001	574,426
Cash and cash equivalents at end of period	590,909	542,805
Non-cash items:
Repurchases of common stock awaiting settlement	11,296	1,345
Fund exchanges within employee deferred compensation trusts	$ 66,645	$ 63,154