Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net earnings (losses)	$ 751,779	$ 1,360,605	$ 1,418,845
Adjustments to reconcile net earnings to net cash from operating activities:
Provisions for losses on accounts receivable	3,943	11,050	7,540
Deferred income tax benefit	(22,916)	(33,240)	(3,690)
Stock compensation expense	58,399	64,397	69,385
Depreciation and amortization	67,760	57,338	51,312
Other, net	8,461	1,252	3,790
Changes in operating assets and liabilities:
Decrease (increase) in accounts receivable	573,724	1,592,341	(1,869,827)
(Decrease) increase in accounts payable and accrued expenses	(300,345)	(798,123)	1,041,805
Decrease (increase) in deferred contract costs	36,952	714,960	(700,273)
(Decrease) increase in contract liabilities	(40,076)	(798,356)	803,837
(Decrease) increase in income taxes payable, net	(77,298)	(55,129)	57,867
(Increase) decrease in other, net	(7,192)	12,580	(12,097)
Net cash from operating activities	1,053,191	2,129,675	868,494
Investing Activities:
Purchase of property and equipment	(39,314)	(86,824)	(36,247)
Other, net	(119)	(890)	(398)
Net cash from investing activities	(39,433)	(87,714)	(36,645)
Financing Activities:
Proceeds from borrowing on lines of credit	32,199	81,756	10,063
Payments on borrowing on lines of credit	(38,143)	(30,289)	(2,551)
Proceeds from issuance of common stock	84,889	80,980	106,105
Repurchases of common stock	(1,392,886)	(1,581,908)	(514,594)
Dividends paid	(202,029)	(213,799)	(195,766)
Payments for taxes related to net share settlement of equity awards	(19,506)	(19,335)	(15,172)
Distribution to noncontrolling interest	(1,089)	(1,945)	(1,631)
Net cash from financing activities	(1,536,565)	(1,684,540)	(613,546)
Effect of exchange rate changes on cash and cash equivalents	1,559	(51,982)	(17,402)
Change in cash and cash equivalents	(521,248)	305,439	200,901
Cash and cash equivalents at beginning of period	2,034,131	1,728,692	1,527,791
Cash and cash equivalents at end of period	1,512,883	2,034,131	1,728,692
Supplemental Cash Flow Information:
Cash paid for income taxes	$ 356,380	$ 566,533	$ 442,549