Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net income	$ 32,637	$ 31,339
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	6,649	6,299
Amortization	375	470
Share-based compensation	3,259	3,321
Equity earnings in unconsolidated investments, net	(65)	(46)
Other	512	681
Changes in operating assets and liabilities, net of effects of acquisitions:
Receivables	(103,122)	(117,377)
Product inventories	(128,206)	(168,518)
Prepaid expenses and other assets	(1,427)	(3,843)
Accounts payable	230,030	222,285
Accrued expenses and other current liabilities	(11,838)	(18,760)
Net cash provided by (used in) operating activities	28,804	(44,149)
Investing activities
Acquisition of businesses, net of cash acquired	(9,370)	(578)
Purchases of property and equipment, net of sale proceeds	(6,739)	(14,639)
Net cash used in investing activities	(16,109)	(15,217)
Financing activities
Proceeds from revolving line of credit	206,190	148,335
Payments on revolving line of credit	(253,249)	(170,012)
Proceeds from asset-backed financing	80,100	80,000
Payments on asset-backed financing	(13,500)	(20,000)
Proceeds from short-term borrowings and current portion of long-term debt	13,713	10,798
Payments on short-term borrowings and current portion of long-term debt	(1,148)	(848)
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	7,071	7,808
Payments of cash dividends	(17,819)	(15,011)
Purchases of treasury stock	(23,097)	(2,592)
Net cash (used in) provided by financing activities	(2,050)	38,205
Effect of exchange rate changes on cash and cash equivalents	1,578	24
Change in cash and cash equivalents	12,223	(21,137)
Cash and cash equivalents at beginning of period	16,358	29,940
Cash and cash equivalents at end of period	$ 28,581	$ 8,803