The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(d))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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Segment Information - Summarized Financial Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 2,052,982us-gaap_SalesRevenueServicesNet	$ 2,171,144us-gaap_SalesRevenueServicesNet	$ 1,864,550us-gaap_SalesRevenueServicesNet	$ 1,762,574us-gaap_SalesRevenueServicesNet	$ 1,817,623us-gaap_SalesRevenueServicesNet	$ 1,645,132us-gaap_SalesRevenueServicesNet	$ 1,474,377us-gaap_SalesRevenueServicesNet	$ 1,585,710us-gaap_SalesRevenueServicesNet	$ 7,851,250us-gaap_SalesRevenueServicesNet	$ 6,522,842us-gaap_SalesRevenueServicesNet	$ 5,920,269us-gaap_SalesRevenueServicesNet
Operating income (loss)									475,575us-gaap_OperatingIncomeLoss	526,928us-gaap_OperatingIncomeLoss	465,122us-gaap_OperatingIncomeLoss
Depreciation									158,110us-gaap_Depreciation	134,110us-gaap_Depreciation	120,303us-gaap_Depreciation
Electric Power Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenues									5,238,627	4,480,647	4,206,509
Operating income (loss)									458,332	521,855	520,834
Depreciation									74,723	63,407	55,205
Oil and Gas Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Revenues									2,444,558	1,869,615	1,534,713
Operating income (loss)									162,797	138,543	55,410
Depreciation									57,414	47,050	43,285
Fiber Optic Licensing and Other [Member]
Segment Reporting Information [Line Items]
Revenues									168,065	172,580	179,047
Operating income (loss)									54,386	55,415	61,299
Depreciation									18,495	16,786	15,173
Corporate and Non-Allocated Costs [Member]
Segment Reporting Information [Line Items]
Operating income (loss)									(199,940)	(188,885)	(172,421)
Depreciation									$ 7,478	$ 6,867	$ 6,640