Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Cash received from customers	$ 1,741,431	$ 1,716,486
Cash paid to suppliers and employees	(1,406,427)	(1,392,653)
Interest paid, net	(11,066)	(11,381)
Income tax payments, net	(51,539)	(42,634)
Investment proceeds and miscellaneous receipts, net	16,336	28,092
Proceeds from forward foreign exchange contracts, net	1,859	185
Net cash provided by operating activities	290,594	298,095
Cash flows from investing activities:
Capital expenditures	(59,685)	(76,934)
Proceeds from dispositions of property, plant and equipment	51	85
Payments for purchases of marketable securities and investments	(184,665)	(266,839)
Proceeds from maturities of marketable securities and investments	242,676	181,108
Proceeds from Sale of Debt Securities, Available-for-sale	75,997	83,315
Payments for Acquisitions, net of cash received	(96,655)	(75,811)
(Payments for) recovery of purchases of intangible assets	(100)	7,383
Proceeds from Divestiture of Businesses	12,240	0
Net cash used in investing activities	(10,141)	(147,693)
Cash flows from financing activities:
Payments on long-term borrowings	(1,780)	(487)
Payments for credit agreement renewal fees	0	(486)
Payments of contingent consideration	(1,724)	(2,477)
Proceeds from Issuance of Common Stock	15,181	9,740
Tax payments from net share settlement	(12,830)	(8,096)
Proceeds from Reissuance of Treasury Stock	0	3,831
Payments for purchases of treasury stock	(100,004)	(20,000)
Net cash used in financing activities	(101,157)	(17,975)
Effect of Exchange Rate on Cash and Cash Equivalents	3,154	(3,239)
Beginning Cash, Cash Equivalents, and Restricted Cash	662,651	434,164
Cash and cash equivalents	840,325	561,071
Ending Cash, Cash Equivalents, and Restricted Cash	845,101	563,352
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	182,450	129,188
Other Current Assets
Cash flows from financing activities:
Restricted Cash, Current	3,763	100
Other Assets
Cash flows from financing activities:
Restricted Cash, Noncurrent	$ 1,013	$ 2,181