Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 123,959	$ 21,557
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	88,282	79,664
Non-cash interest expense, net	1,615	1,473
Non-cash stock-based compensation expense	7,166	7,405
Provision for deferred income taxes	76,584	1,155
Equity in earnings of unconsolidated affiliates	(7,706)	(3,555)
(Gains) losses on sales of assets, net, including fixed assets held-for-sale	(1,873)	1,177
Other non-cash items, net	13,190	2,098
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(388,818)	(179,372)
Inventories	28,295	(26,454)
Other assets, current and long-term portion	(81,286)	32,433
Accounts payable and accrued expenses	113,975	123,958
Billings in excess of costs and earnings	(58,594)	(18,856)
Book overdrafts	(9,760)	10,075
Other liabilities, current and long-term portion	6,978	(24,270)
Net cash (used in) provided by operating activities	(87,993)	28,488
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(37,444)	(4,102)
Capital expenditures	(56,853)	(63,893)
Proceeds from sale of property and equipment	7,369	10,163
Payments for other investments	(74,482)	(2,735)
Proceeds from other investments	12,118	695
Net cash used in investing activities	(149,292)	(59,872)
Cash flows from financing activities:
Proceeds from credit facilities	1,153,230	684,287
Repayments of credit facilities	(869,100)	(604,640)
Repayments of other borrowings	(10,291)	(5,993)
Payments of capital lease obligations	(30,858)	(27,506)
Payments of acquisition-related contingent consideration	(18,843)	(14,572)
Distributions to non-controlling interests	(1,280)	0
Proceeds from stock-based awards, net	5	3,338
Other financing activities, net	(6,240)	1,132
Net cash provided by financing activities	216,623	36,046
Effect of currency translation on cash	125	(888)
Net (decrease) increase in cash and cash equivalents	(20,537)	3,774
Cash and cash equivalents - beginning of period	38,767	4,984
Cash and cash equivalents - end of period	18,230	8,758
Supplemental cash flow information:
Interest paid	25,743	22,647
Income taxes paid, net of refunds	76,633	7,131
Supplemental disclosure of non-cash information:
Equipment acquired under capital lease and financing arrangements	109,914	3,481
Accrued capital expenditures	$ 1,499	$ 6,090