Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
OPERATING ACTIVITIES
Net income	$ 844,331	$ 614,147
Adjustments to reconcile net income to net cash used for operating activities:
Depreciation and amortization	68,723	68,621
Provision for credit losses	(2,407)	3,979
Stock-based compensation	78,346	93,962
Deferred income taxes	(76,362)	(11,683)
Excess tax benefit on stock-based compensation	(12,440)	(10,830)
Other operating activities	(24,011)	1,384
Changes in operating elements, net of acquisitions:
Receivables	66,536	(1,290,485)
Contract assets	90,481	(220,889)
Prepaid expenses and other	13,437	(38,525)
Accounts payable and outstanding checks	(109,493)	595,036
Accrued compensation	6,701	35,413
Accrued transportation expense	(62,278)	165,580
Accrued income taxes	(24,202)	6,400
Other accrued liabilities	22,209	4,947
Other assets and liabilities	(2,782)	2,043
Net cash provided by operating activities	876,789	19,100
INVESTING ACTIVITIES
Purchases of property and equipment	(50,719)	(26,503)
Purchases and development of software	(49,935)	(26,062)
Acquisitions, net of cash acquired	0	14,749
Proceeds from sale of property and equipment	63,208	0
Net cash used for investing activities	(37,446)	(67,314)
FINANCING ACTIVITIES
Proceeds from stock issued for employee benefit plans	93,415	43,183
Stock tendered for payment of withholding taxes	(26,597)	(25,246)
Repurchase of common stock	(1,023,578)	(428,801)
Cash dividends	(216,258)	(208,926)
Proceeds from long-term borrowings	200,000	0
Payments on long-term borrowings	0	(2,048)
Proceeds from short-term borrowings	3,674,000	2,768,000
Payments on short-term borrowings	(3,595,000)	(2,136,251)
Net cash (used for) provided by financing activities	(894,018)	9,911
Effect of exchange rates on cash and cash equivalents	(15,206)	(2,844)
Net change in cash and cash equivalents	(69,881)	(41,147)
Cash and cash equivalents, beginning of period	257,413	243,796
Cash and cash equivalents, end of period	$ 187,532	$ 202,649