Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income (loss)		$ 21,557	$ (10,208)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		79,664	85,852
Non-cash interest expense, net		1,473	1,324
Non-cash stock-based compensation expense		7,405	6,320
Excess tax benefit from stock-based compensation	[1]	(1,132)	(53)
Provision for (benefit from) deferred income taxes		1,155	(10,026)
Other non-cash items		3,230	736
Losses (gains) on sales of assets, including estimated losses on fixed assets held-for-sale		1,177	(1,427)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable		(179,372)	159,384
Inventories		(26,454)	9,356
Other assets, current and long-term portion		28,878	1,023
Accounts payable and accrued expenses		123,958	(37,335)
Billings in excess of costs and earnings		(18,856)	(33,100)
Book overdrafts		10,075	1,217
Other liabilities, current and long-term portion		(24,270)	(11,774)
Net cash provided by operating activities		28,488	161,289
Cash flows used in investing activities:
Cash paid for acquisitions, net of cash acquired		(4,102)	(148)
Capital expenditures		(63,893)	(48,431)
Proceeds from sale of property and equipment		10,163	4,146
Payments for other investments		(2,040)	(65,150)
Net cash used in investing activities		(59,872)	(109,583)
Cash flows provided by (used in) financing activities:
Proceeds from credit facilities		684,287	844,494
Repayments of credit facilities		(604,640)	(741,302)
Repayments of other borrowings		(5,993)	(6,683)
Payments of capital lease obligations		(27,506)	(28,469)
Repurchase of common stock		0	(100,000)
Proceeds from stock-based awards, net of tax withholdings		3,338	1,849
Excess tax benefit from stock-based compensation		1,132	53
Payments of acquisition-related contingent consideration		(14,572)	(39,257)
Payments of financing costs		0	(1,053)
Net cash provided by (used in) financing activities		36,046	(70,368)
Effect of currency translation on cash		(888)	(642)
Net increase (decrease) in cash and cash equivalents		3,774	(19,304)
Cash and cash equivalents - beginning of period		4,984	24,059
Cash and cash equivalents - end of period		8,758	4,755
Supplemental cash flow information:
Interest paid		22,647	22,837
Income taxes paid, net of refunds		7,131	5,429
Supplemental disclosure of non-cash information:
Equipment acquired under capital lease		2,627	16,084
Accrued capital expenditures		6,090	5,304
Equipment [Member]
Supplemental disclosure of non-cash information:
Equipment acquired under financing arrangements		$ 854	$ 5,758

[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.