Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 227,406	$ 188,160
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	156,478	138,384
Non-cash interest expense, net	1,836	2,375
Non-cash stock-based compensation expense	10,086	10,551
Provision for deferred income taxes	51,405	92,188
Equity in earnings of unconsolidated affiliates	(19,080)	(15,105)
Gains on sales of assets, net, including fixed assets held-for-sale	(12,021)	(3,335)
Other non-cash items, net	5,055	14,920
Changes in assets and liabilities, net of acquisitions:
Accounts receivable, net	(763,893)	(334,383)
Inventories	(37,025)	33,579
Other assets, current and long-term portion	34,495	(61,900)
Accounts payable and accrued expenses	376,440	132,963
Billings in excess of costs and earnings	(9,432)	(54,199)
Book overdrafts	(8,502)	(4,603)
Other liabilities, current and long-term portion	13,522	26,863
Net cash provided by operating activities	26,770	166,458
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(6,684)	(115,995)
Capital expenditures	(134,214)	(83,330)
Proceeds from sale of property and equipment	29,676	13,585
Payments for other investments	(36,330)	(77,105)
Proceeds from other investments	5,415	13,416
Net cash used in investing activities	(142,137)	(249,429)
Cash flows from financing activities:
Proceeds from credit facilities	2,422,556	2,002,430
Repayments of credit facilities	(1,997,392)	(1,840,409)
Repayments of other borrowings	(15,830)	(12,080)
Payments of capital lease obligations	(54,560)	(48,748)
Payments of acquisition-related contingent consideration	(15,929)	(6,676)
Repurchase of common stock	(198,448)	0
Distributions to non-controlling interests	(559)	(1,280)
Proceeds from stock-based awards, net	3,086	853
Other financing activities	0	(6,301)
Net cash provided by financing activities	142,924	87,789
Effect of currency translation on cash	601	237
Net increase in cash and cash equivalents	28,158	5,055
Cash and cash equivalents - beginning of period	40,326	38,767
Cash and cash equivalents - end of period	68,484	43,822
Supplemental cash flow information:
Interest paid	65,788	47,163
Income tax (refunds) payments, net	(12,736)	77,533
Supplemental disclosure of non-cash information:
Additions to acquisition-related contingent consideration	5,711	89,614
Equipment acquired under capital lease and financing arrangements	48,498	129,567
Accrued capital expenditures	$ 7,953	$ 1,345