Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 293,411	$ 227,406
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	174,171	156,478
Non-cash interest expense, net	1,691	1,836
Non-cash stock-based compensation expense	12,132	10,086
Provision for deferred income taxes	8,546	51,405
Equity in earnings of unconsolidated affiliates	(19,778)	(19,080)
Gains on sales of assets, net, including fixed assets held-for-sale	(9,627)	(12,021)
Other non-cash items, net	(1,515)	5,055
Changes in assets and liabilities, net of acquisitions:
Accounts receivable, net	731	(763,893)
Inventories	21,293	(37,025)
Other assets, current and long-term portion	16,641	34,495
Accounts payable and accrued expenses	(30,641)	367,938
Billings in excess of costs and earnings	(73,231)	(9,432)
Other liabilities, current and long-term portion	47,570	13,522
Net cash provided by operating activities	441,394	26,770
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(94,647)	(6,684)
Capital expenditures	(85,095)	(134,214)
Proceeds from sale of property and equipment	27,102	29,676
Payments for other investments	(5,589)	(36,330)
Proceeds from other investments	14,705	5,415
Net cash used in investing activities	(143,524)	(142,137)
Cash flows from financing activities:
Proceeds from credit facilities	2,185,714	2,422,556
Repayments of credit facilities	(2,371,965)	(1,997,392)
Repayments of other borrowings, net	(333)	(15,830)
Payments of finance lease obligations	(59,045)	(54,560)
Payments of acquisition-related contingent consideration	(29,267)	(15,929)
Proceeds from (distributions to) non-controlling interests	584	(559)
Proceeds from stock-based awards, net	3,380	3,086
Repurchases of common stock	(5,652)	(198,448)
Other financing activities, net	(5,459)	0
Net cash (used in) provided by financing activities	(282,043)	142,924
Effect of currency translation on cash	(154)	601
Net increase in cash and cash equivalents	15,673	28,158
Cash and cash equivalents - beginning of period	27,422	40,326
Cash and cash equivalents - end of period	43,095	68,484
Supplemental cash flow information:
Interest paid	73,570	65,788
Income tax payments (refunds), net	73,502	(12,736)
Supplemental disclosure of non-cash information:
Additions to property and equipment from finance leases	$ 163,458	$ 48,498