Condensed Unaudited Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 93,392		$ 99,621
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	111,996		103,111
Non-cash interest expense, including write-off of deferred financing costs on redeemed debt	6,052		8,397
Non-cash stock-based compensation expense	11,584		9,647
Excess tax benefit from stock-based compensation	(3,494)	[1]	(4,446)	[1]
Provision for deferred income taxes	4,294		9,439
(Gains) losses on sales of assets, including impairment charges on discontinued operations	(4,068)		1,152
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(131,175)		(271,010)
Inventories	(27,553)		20,484
Other assets, current and non-current portion	5,202		18,610
Accounts payable and accrued expenses	14,521		126,784
Billings in excess of costs and earnings	4,171		(19,776)
Book overdrafts	(10,399)		2,791
Other liabilities, current and non-current portion	5,857		16,027
Net cash provided by operating activities	81,019		129,256
Cash flows (used in) provided by investing activities:
Cash paid for acquisitions, net of cash acquired	(162,901)		(146,598)
Capital expenditures	(90,962)		(101,411)
Proceeds from sale of property and equipment	12,204		8,288
Proceeds from disposal of business, net of cash divested	0		(4,332)
(Payments for) proceeds from other investments, net	(1,046)		3,852
Net cash used in investing activities	(242,705)		(240,201)
Cash flows provided by (used in) financing activities:
Proceeds from credit facility	1,319,623		766,154
Repayments of credit facility	(955,151)		(860,070)
Proceeds from issuance of senior notes	0		400,000
Repayment of senior notes, including convertible notes	(105,325)		(150,000)
Repayments of other borrowings	(15,827)		(24,246)
Payments of capital lease obligations	(38,358)		(32,214)
Excess tax benefit from stock-based compensation	3,494		4,446
Payments of financing costs, including call premiums on extinguishment of debt	(1,455)		(11,835)
Net cash provided by financing activities	146,978		87,144
Effect of currency translation on cash	(1,152)		(118)
Net decrease in cash and cash equivalents	(15,860)		(23,919)
Cash and cash equivalents - beginning of period	22,927		26,767
Cash and cash equivalents - end of period	7,067		2,848
Supplemental cash flow information:
Interest paid	35,106		30,851
Income taxes paid, net of refunds	46,423		49,722
Supplemental disclosure of non-cash information:
Equipment acquired under capital lease	55,488		82,737
2011 4.0% Notes [Member]
Supplemental disclosure of non-cash information:
Premium shares, conversion of convertible notes	114,785		0
Equipment [Member]
Supplemental disclosure of non-cash information:
Equipment acquired under financing arrangements	6,851		24,100
Earn-Out Arrangements [Member]
Cash flows provided by (used in) financing activities:
Payments of acquisition-related contingent consideration	(60,341)		(12,848)
Supplemental disclosure of non-cash information:
Acquisition-related contingent consideration, new business combinations	34,988		29,971
Stock Compensation Plan [Member]
Cash flows provided by (used in) financing activities:
Proceeds from stock-based awards, net of tax withholdings	318		7,757
Payments of acquisition-related contingent consideration	3,800		12,200
Operating Expense [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for losses on operating assets	1,136		6,300
Contracts Accounted for Under Percentage of Completion [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for losses on construction projects, net	$ (497)		$ 2,125

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