Segments and Operations by Geographic Area (Schedule of Segment Reporting Information, by Segment) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Revenue	$ 977,624,000	$ 988,874,000	$ 1,896,272,000	$ 1,727,131,000
Depreciation			65,355,000	42,946,000
Amortization			9,400,000	5,700,000
Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	977,600,000	988,900,000	1,896,300,000	1,727,100,000
EBITDA	102,700,000	82,400,000	176,200,000	131,500,000
Depreciation	33,602,000	21,763,000	65,355,000	42,480,000
Amortization	5,300,000	2,800,000	9,400,000	5,700,000
Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	28,300,000	18,900,000	55,900,000	36,800,000
Intersegment Elimination [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	(1,200,000)	(100,000)	(2,000,000)	(900,000)
EBITDA	0	100,000	0	0
Amortization	0	0	0	0
Intersegment Elimination [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	0	0	0	0
Communications [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	496,600,000	431,900,000	921,600,000	821,000,000
EBITDA	63,400,000	47,000,000	109,800,000	79,800,000
Amortization	1,500,000	400,000	2,600,000	900,000
Communications [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	7,600,000	6,800,000	14,800,000	13,000,000
Oil and Gas [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	296,900,000	263,700,000	615,700,000	431,400,000
EBITDA	51,200,000	15,700,000	93,600,000	28,300,000
Amortization	3,000,000	500,000	5,200,000	900,000
Oil and Gas [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	16,100,000	9,000,000	32,500,000	17,700,000
Electrical Transmission [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	118,600,000	88,900,000	203,100,000	153,300,000
EBITDA	11,500,000	12,100,000	14,900,000	20,500,000
Amortization	300,000	1,200,000	600,000	2,600,000
Electrical Transmission [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	2,500,000	1,400,000	4,500,000	2,800,000
Power Generation and Industrial [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	63,300,000	198,300,000	152,200,000	315,700,000
EBITDA	(8,000,000)	13,400,000	(8,200,000)	18,400,000
Amortization	500,000	700,000	1,000,000	1,300,000
Power Generation and Industrial [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	1,200,000	1,000,000	2,400,000	1,900,000
All Other Segments [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	3,400,000	6,200,000	5,700,000	6,600,000
EBITDA	400,000	800,000	400,000	600,000
Amortization	0	0	0	0
All Other Segments [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	0	0	0	0
Corporate [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue	0	0	0	0
EBITDA	(15,800,000)	(6,700,000)	(34,300,000)	(16,100,000)
Amortization	0	0	0	0
Corporate [Member] | Reportable Segment [Member] | Segment, Continuing Operations [Member] | Property and Equipment [Member]
Segment Reporting Information [Line Items]
Depreciation	$ 900,000	$ 700,000	$ 1,700,000	$ 1,400,000