Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating activities
Net Income	$ 358,350	$ 188,467
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Depreciation	13,884	13,993
Amortization	723	655
Share-based compensation	7,549	7,221
Equity earnings in unconsolidated investments, net	(132)	(162)
Impairment of goodwill and other assets	0	6,944
Other	4,812	3,171
Changes in operating assets and liabilities, net of effects of acquisitions:
Receivables	(295,342)	(229,506)
Product inventories	(114,792)	75,199
Prepaid expenses and other assets	(16,865)	(677)
Accounts payable	170,368	84,190
Accrued expenses and other current liabilities	58,673	71,705
Net Cash Provided by operating activities	187,228	221,200
Investing activities
Acquisition of businesses, net of cash acquired	(15,162)	(13,711)
Purchases of property and equipment, net of sale proceeds	(17,333)	(13,031)
Net cash used in investing activities	(32,495)	(26,742)
Financing activities
Proceeds from revolving line of credit	549,008	318,155
Payments on revolving line of credit	(505,636)	(504,140)
Proceeds from asset-backed financing	260,000	191,700
Payments on asset-backed financing	(290,000)	(71,700)
Payments on term facility	(4,625)	(4,625)
Proceeds from short-term borrowings and current portion of long-term debt	4,466	10,731
Payments on short-term borrowings and current portion of long-term debt	(6,277)	(12,918)
Payments of deferred and contingent acquisition consideration	(362)	(281)
Payments of deferred financing costs	0	(12)
Proceeds from stock issued under share-based compensation plans	7,918	10,811
Payments of cash dividends	(55,418)	(45,312)
Purchases of treasury stock	(90,135)	(70,203)
Net cash used in financing activities	(131,061)	(177,794)
Effect of exchange rate changes on cash and cash equivalents	665	(1,062)
Change in cash and cash equivalents	24,337	15,602
Cash and cash equivalents at beginning of period	34,128	28,583
Cash and cash equivalents at end of period	$ 58,465	$ 44,185