Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net (loss) income		$ (2,766)	$ 94,855
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization		128,048	111,996
Non-cash interest expense		2,036	6,052
Non-cash stock-based compensation expense		9,486	11,584
Excess tax benefit from stock-based compensation	[1]	(56)	(3,494)
(Benefit from) provision for deferred income taxes		(9,076)	4,294
Other non-cash items		1,783	1,136
Gains on sales of assets		(2,619)	(4,068)
Non-cash change in estimated fair value of acquisition-related contingent consideration		(7,980)	0
Changes in assets and liabilities, net of acquisitions:
Accounts receivable		252,333	(126,950)
Inventories		22,406	(27,553)
Other assets, current and long-term portion		(13,915)	5,202
Accounts payable and accrued expenses		(76,747)	15,419
Billings in excess of costs and earnings		(31,168)	2,896
Book overdrafts		(7,830)	(10,399)
Other liabilities, current and long-term portion		(3,333)	49
Net cash provided by operating activities		260,602	81,019
Cash flows used in investing activities:
Cash paid for acquisitions, net of cash acquired		(148)	(162,901)
Capital expenditures		(70,766)	(90,962)
Proceeds from sale of property and equipment		9,763	12,204
Payments for other investments, net		(109,299)	(1,046)
Net cash used in investing activities		(170,450)	(242,705)
Cash flows (used in) provided by financing activities:
Proceeds from credit facilities		1,329,610	1,319,623
Repayments of credit facilities		(1,240,122)	(955,151)
Repayments of senior convertible notes		0	(105,325)
Repayments of other borrowings		(10,568)	(15,827)
Payments of capital lease obligations		(40,687)	(38,358)
Repurchase of common stock		(100,000)	0
Proceeds from stock-based awards, net of tax withholdings		1,743	318
Excess tax benefit from stock-based compensation		56	3,494
Payments of acquisition-related contingent consideration		(44,757)	(60,341)
Payments of financing costs		(2,435)	(1,455)
Net cash (used in) provided by financing activities		(107,160)	146,978
Effect of currency translation on cash		103	(1,152)
Net decrease in cash and cash equivalents		(16,905)	(15,860)
Cash and cash equivalents - beginning of period		24,059	22,927
Cash and cash equivalents - end of period		7,154	7,067
Supplemental cash flow information:
Interest paid		41,014	35,106
Income taxes paid, net of refunds		5,841	46,423
Supplemental disclosure of non-cash information:
Equipment acquired under capital lease		18,030	55,488
2011 Convertible Notes [Member]
Supplemental disclosure of non-cash information:
Premium shares, conversion of convertible notes			114,785
Earn-Out Arrangements [Member]
Supplemental disclosure of non-cash information:
Acquisition-related contingent consideration, new business combinations			33,612
Equipment [Member]
Supplemental disclosure of non-cash information:
Equipment acquired under financing arrangements		$ 7,949	$ 6,851

[1] Excess tax benefits, which represent cash flows from tax deductions in excess of the tax effect of compensation expense associated with exercised stock options and vested restricted shares, are classified as financing cash flows in the Company’s condensed unaudited consolidated statements of cash flows.