Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 155,315	$ 128,771
Accounts receivable, net of allowances of $2,727 and $5,226	1,493,255	1,621,133
Costs and estimated earnings in excess of billings on uncompleted contracts	383,218	317,745
Inventories	72,643	75,285
Prepaid expenses and other current assets	143,943	134,585
Total current assets	2,248,374	2,277,519
Property and equipment, net of accumulated depreciation of $791,110 and $755,272	1,153,884	1,101,959
Other assets, net	86,558	76,333
Other intangible assets, net of accumulated amortization of $275,755 and $264,674	211,303	205,074
Goodwill	1,595,400	1,552,658
Total assets	5,295,519	5,213,543
Current Liabilities:
Current maturities of long-term debt and short-term borrowings	4,154	7,067
Accounts payable and accrued expenses	791,214	782,134
Billings in excess of costs and estimated earnings on uncompleted contracts	437,455	399,230
Current liabilities of discontinued operations	3,088	15,313
Total current liabilities	1,235,911	1,203,744
Long-term debt and notes payable, net of current maturities	404,058	475,364
Deferred income taxes	205,945	186,491
Insurance and other non-current liabilities	276,376	260,129
Total liabilities	$ 2,122,290	$ 2,125,728
Commitments and Contingencies
Equity:
Common stock, value	$ 2	$ 2
Additional paid-in capital	3,516,239	3,497,740
Retained earnings	1,698,194	1,677,698
Accumulated other comprehensive loss	(234,103)	(294,689)
Treasury stock, 75,337,308 and 74,991,343 common shares, at cost	(1,809,787)	(1,795,257)
Total stockholders' equity	3,170,545	3,085,494
Non-controlling interests	2,684	2,321
Total equity	3,173,229	3,087,815
Total liabilities and equity	$ 5,295,519	$ 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