Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 162,344	$ 128,771
Accounts receivable, net of allowances of $2,719 and $5,226	1,384,554	1,621,133
Costs and estimated earnings in excess of billings on uncompleted contracts	466,476	317,745
Inventories	74,976	75,285
Prepaid expenses and other current assets	156,037	134,585
Total current assets	2,244,387	2,277,519
Property and equipment, net of accumulated depreciation of $824,108 and $755,272	1,160,870	1,101,959
Other assets, net	93,033	76,333
Other intangible assets, net of accumulated amortization of $283,889 and $264,674	203,256	205,074
Goodwill	1,595,555	1,552,658
Total assets	5,297,101	5,213,543
Current Liabilities:
Current maturities of long-term debt and short-term borrowings	5,603	7,067
Accounts payable and accrued expenses	811,521	782,134
Billings in excess of costs and estimated earnings on uncompleted contracts	388,314	399,230
Current liabilities of discontinued operations	2,651	15,313
Total current liabilities	1,208,089	1,203,744
Long-term debt and notes payable, net of current maturities	401,119	475,364
Deferred income taxes	200,683	186,491
Insurance and other non-current liabilities	284,036	260,129
Total liabilities	2,093,927	2,125,728
Commitments and Contingencies
Equity:
Common stock, value	2	2
Additional paid-in capital	3,676,910	3,497,740
Retained earnings	1,714,756	1,677,698
Accumulated other comprehensive loss	(231,020)	(294,689)
Treasury stock, 84,757,044 and 74,991,343 common shares, at cost	(1,960,325)	(1,795,257)
Total stockholders' equity	3,200,323	3,085,494
Non-controlling interests	2,851	2,321
Total equity	3,203,174	3,087,815
Total liabilities and equity	5,297,101	5,213,543
Exchangeable Shares [Member]
Equity:
Common stock, value
Series F Preferred Stock [Member]
Equity:
Preferred Stock, value
Series G Preferred Stock [Member]
Equity:
Preferred Stock, value