Segments and Operations by Geographic Area Segments and Operations by Geographic Area (Schedule of Segment Reporting Information, by Segment) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenue	$ 932,300,000	$ 1,067,300,000	$ 988,900,000	$ 738,300,000	$ 731,600,000	$ 816,200,000	$ 709,900,000	$ 573,600,000	$ 3,726,789,000	$ 2,831,292,000	$ 2,143,024,000
Amortization									12,200,000	13,900,000
Total assets	2,407,934,000				2,094,705,000				2,407,934,000	2,094,705,000	1,655,800,000
Capital expenditures									79,686,000	71,710,000	30,383,000
Segment, Continuing Operations [Member]
Segment Reporting Information [Line Items]
Revenue									3,726,800,000	2,831,300,000	2,143,000,000
EBITDA									322,100,000	267,900,000	200,100,000
Depreciation									79,800,000	60,200,000	44,000,000
Amortization									12,200,000	13,900,000	12,900,000
Total assets	2,381,700,000				1,942,400,000				2,381,700,000	1,942,400,000	1,508,700,000
Capital expenditures									79,400,000	71,000,000	27,800,000
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Revenue									(1,900,000)	(800,000)	(3,000,000)
EBITDA									0	0	0
Depreciation									0	0	0
Amortization									0	0	0
Total assets	15,000,000				(10,200,000)				15,000,000	(10,200,000)	(9,600,000)
Capital expenditures									0	0	0
Communications [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									1,772,700,000	1,635,100,000	1,190,600,000
EBITDA									192,000,000	154,300,000	107,900,000
Depreciation									27,000,000	22,700,000	13,400,000
Amortization									2,100,000	1,800,000	800,000
Total assets	829,200,000				837,100,000				829,200,000	837,100,000	598,300,000
Capital expenditures									19,200,000	23,000,000	11,600,000
Oil and Gas [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									959,000,000	774,300,000	562,600,000
EBITDA									99,400,000	80,100,000	111,300,000
Depreciation									39,600,000	26,800,000	20,800,000
Amortization									2,500,000	4,000,000	7,200,000
Total assets	805,500,000				494,600,000				805,500,000	494,600,000	392,200,000
Capital expenditures									40,300,000	25,700,000	10,500,000
Electrical Transmission [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									312,200,000	198,300,000	67,000,000
EBITDA									38,700,000	28,700,000	(3,700,000)
Depreciation									6,000,000	4,000,000	3,100,000
Amortization									5,000,000	4,400,000	100,000
Total assets	309,900,000				253,700,000				309,900,000	253,700,000	38,500,000
Capital expenditures									11,500,000	9,300,000	0
Power Generation and Industrial [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									668,100,000	219,600,000	325,600,000
EBITDA									32,000,000	(3,200,000)	16,900,000
Depreciation									4,100,000	3,900,000	4,300,000
Amortization									2,600,000	3,700,000	4,600,000
Total assets	321,600,000				269,400,000				321,600,000	269,400,000	283,800,000
Capital expenditures									5,600,000	4,600,000	3,100,000
All Other Segments [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									16,700,000	4,800,000	200,000
EBITDA									2,000,000	400,000	(1,000,000)
Depreciation									100,000	100,000	0
Amortization									0	0	0
Total assets	7,000,000				3,800,000				7,000,000	3,800,000	900,000
Capital expenditures									0	0	100,000
Corporate [Member] | Reportable Segment [Member]
Segment Reporting Information [Line Items]
Revenue									0	0	0
EBITDA									(42,000,000)	7,600,000	(31,300,000)
Depreciation									3,000,000	2,700,000	2,400,000
Amortization									0	0	200,000
Total assets	93,500,000				94,000,000				93,500,000	94,000,000	204,600,000
Capital expenditures									$ 2,900,000	$ 8,500,000	$ 2,500,000