Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Net Income	$ 243,551	$ 217,649
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	20,648	19,499
Amortization	1,049	1,408
Share-based compensation	10,243	9,793
Equity earnings in unconsolidated investments, net	(210)	(167)
Other	5,334	3,584
Changes in operating assets and liabilities, net of effects of acquisitions:
Receivables	(98,538)	(93,911)
Product inventories	68,827	(80,142)
Prepaid expenses and other assets	1,231	143
Accounts payable	(29,782)	(40,143)
Accrued expenses and other current liabilities	20,900	13,547
Net cash provided by (used in) operating activities	243,253	51,260
Investing activities
Acquisition of businesses, net of cash acquired	(8,913)	(578)
Purchases of property and equipment, net of sale proceeds	(26,926)	(27,976)
Net cash used in investing activities	(35,839)	(28,554)
Financing activities
Proceeds from revolving line of credit	836,534	820,967
Payments on revolving line of credit	(1,011,430)	(813,996)
Proceeds from asset-backed financing	189,000	193,400
Payments on asset-backed financing	(136,300)	(138,400)
Proceeds from short-term borrowings and current portion of long-term debt	27,633	16,118
Payments on short-term borrowings and current portion of long-term debt	(24,962)	(17,610)
Payments of deferred and contingent acquisition consideration	(311)	(265)
Payments of deferred financing costs	0	(8)
Proceeds from stock issued under share-based compensation plans	17,042	12,732
Payments of cash dividends	(61,752)	(51,371)
Purchases of treasury stock	(23,188)	(38,906)
Net cash (used in) provided by financing activities	(187,734)	(17,339)
Effect of exchange rate changes on cash and cash equivalents	655	386
Change in cash and cash equivalents	20,335	5,753
Cash and cash equivalents at beginning of period	16,358	29,940
Cash and cash equivalents at end of period	$ 36,693	$ 35,693