Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities
Net income	$ 116,891	$ 101,610
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation	11,617	9,743
Amortization	743	735
Share-based compensation	6,299	4,850
Excess tax benefits from share-based compensation	0	(3,203)
Equity earnings in unconsolidated investments, net	(78)	(62)
Other	2,122	2,270
Changes in operating assets and liabilities, net of effects of acquisitions:
Receivables	(199,055)	(187,526)
Product inventories	(53,546)	(14,481)
Prepaid expenses and other assets	(2,389)	(1,729)
Accounts payable	38,673	15,041
Accrued expenses and other current liabilities	37,378	58,995
Net cash used in operating activities	(41,345)	(13,757)
Investing activities
Acquisition of businesses, net of cash acquired	(3,296)	(19,211)
Purchase of property and equipment, net of sale proceeds	(34,495)	(25,779)
Payments to fund credit agreement	0	(2,232)
Collections from credit agreement	0	2,475
Other investments, net	3	17
Net cash used in investing activities	(37,788)	(44,730)
Financing activities
Proceeds from revolving line of credit	606,623	629,351
Payments on revolving line of credit	(641,752)	(604,470)
Proceeds from asset-backed financing	156,600	145,000
Payments on asset-backed financing	(20,100)	(2,800)
Proceeds from short-term borrowings, long-term debt and other long-term liabilities	22,609	12,110
Payments on short-term borrowings, long-term debt and other long term liabilities	(8,813)	(6,987)
Payments of deferred and contingent acquisition consideration	(199)	0
Purchase of redeemable noncontrolling interest	(2,573)	0
Excess tax benefits from share-based compensation	0	3,203
Proceeds from stock issued under share-based compensation plans	7,502	5,699
Payments of cash dividends	(28,108)	(23,957)
Purchases of treasury stock	(8,672)	(80,478)
Net cash provided by financing activities	83,117	76,671
Effect of exchange rate changes on cash and cash equivalents	726	(870)
Change in cash and cash equivalents	4,710	17,314
Cash and cash equivalents at beginning of period	21,956	13,237
Cash and cash equivalents at end of period	$ 26,666	$ 30,551