Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net Income	$ 543,015	$ 307,565
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation	21,027	20,979
Amortization	1,064	975
Share-based compensation	11,755	11,095
Equity earnings in unconsolidated investments, net	(224)	(248)
Impairment of goodwill and other assets	0	6,944
Other	5,256	1,092
Changes in operating assets and liabilities, net of effects of acquisitions:
Receivables	(186,772)	(135,129)
Product inventories	(267,341)	99,767
Prepaid expenses and other assets	(22,674)	311
Accounts payable	146,616	3,385
Accrued expenses and other current liabilities	107,343	72,178
Net Cash Provided by operating activities	359,065	388,914
Investing activities
Acquisition of businesses, net of cash acquired	(17,887)	(24,655)
Purchases of property and equipment, net of sale proceeds	(24,223)	(16,897)
Net cash used in investing activities	(42,110)	(41,552)
Financing activities
Proceeds from revolving line of credit	791,508	749,840
Payments on revolving line of credit	(730,277)	(909,637)
Proceeds from asset-backed financing	310,000	261,700
Payments on asset-backed financing	(415,000)	(266,700)
Payments on term facility	(6,938)	(6,938)
Proceeds from short-term borrowings and current portion of long-term debt	7,880	13,255
Payments on short-term borrowings and current portion of long-term debt	(9,006)	(13,291)
Payments of deferred and contingent acquisition consideration	(362)	(281)
Payments of deferred financing costs	(1,610)	(12)
Proceeds from stock issued under share-based compensation plans	11,524	16,696
Payments of cash dividends	(87,509)	(68,599)
Purchases of treasury stock	(137,975)	(76,194)
Net cash used in financing activities	(267,765)	(300,161)
Effect of exchange rate changes on cash and cash equivalents	157	(1,035)
Change in cash and cash equivalents	49,347	46,166
Cash and cash equivalents at beginning of period	34,128	28,583
Cash and cash equivalents at end of period	$ 83,475	$ 74,749