Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Net earnings	$ 1,360,605	$ 1,418,845	$ 698,214
Adjustments to reconcile net earnings to net cash from operating activities:
Provisions for losses on accounts receivable	11,050	7,540	5,584
Deferred income tax (benefit) expense	(33,240)	(3,690)	8,371
Stock compensation expense	64,397	69,385	62,498
Depreciation and amortization	57,338	51,312	56,959
Other, net	1,252	3,790	3,960
Changes in operating assets and liabilities:
Decrease (Increase) in accounts receivable	1,592,341	(1,869,827)	(647,193)
(Decrease) increase in accounts payable and accrued expenses	(798,123)	1,041,805	430,452
Decrease (Increase) in deferred contract costs	714,960	(700,273)	(189,447)
(Decrease) increase in contract liabilities	(798,356)	803,837	217,699
(Decrease) increase in income taxes payable, net	(55,129)	57,867	8,502
Decrease (increase) in other, net	12,580	(12,097)	(630)
Net cash from operating activities	2,129,675	868,494	654,969
Investing Activities:
Purchase of property and equipment	(86,824)	(36,247)	(47,543)
Other, net	(890)	(398)	1,516
Net cash from investing activities	(87,714)	(36,645)	(46,027)
Financing Activities:
Proceeds from borrowing on lines of credit	81,756	10,063	257
Payments from borrowing on lines of credit	(30,289)	(2,551)	(214)
Proceeds from issuance of common stock	80,980	106,105	186,345
Repurchases of common stock	(1,581,908)	(514,594)	(332,387)
Dividends paid	(213,799)	(195,766)	(174,929)
Payments for taxes related to net share settlement of equity awards	(19,335)	(15,172)	(10,566)
Distribution to noncontrolling interest	(1,945)	(1,631)	0
Net cash from financing activities	(1,684,540)	(613,546)	(331,494)
Effect of exchange rate changes on cash and cash equivalents	(51,982)	(17,402)	19,852
Change in cash and cash equivalents	305,439	200,901	297,300
Cash and cash equivalents at beginning of period	1,728,692	1,527,791	1,230,491
Cash and cash equivalents at end of period	2,034,131	1,728,692	1,527,791
Supplemental Cash Flow Information:
Cash paid for income taxes	$ 566,533	$ 442,549	$ 239,849