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Business And Organization (Narrative) (Detail) | 3 Months Ended | 9 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended | 3 Months Ended | 12 Months Ended
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Mar. 31, 2012 Entity | Sep. 30, 2011 Entity | Sep. 30, 2012 | Sep. 30, 2011 | Dec. 31, 2011 Entity | Jun. 30, 2012 Electric Power Division [Member] United States [Member] Entity | Mar. 31, 2012 Electric Power Division [Member] United States [Member] Entity | Dec. 31, 2011 Electric Power Division [Member] United States [Member] Entity | Mar. 31, 2012 Electric Power Division [Member] Canada [Member] Entity | Sep. 30, 2011 Electric Power Division [Member] Canada [Member] Entity | Dec. 31, 2011 Electric Power Division [Member] Canada [Member] Entity | Mar. 31, 2012 Natural Gas And Pipeline Division [Member] United States [Member] Entity | Sep. 30, 2011 Natural Gas And Pipeline Division [Member] Australia [Member] Entity | Dec. 31, 2011 Natural Gas And Pipeline Division [Member] Australia [Member] Entity
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fiber Optic Licensing Terms, Minimum in years |  |  | 5 years | 5 years |  |  |  |  |  |  |  |  |  |
Fiber Optic Licensing Terms, Maximum in years |  |  | 25 years | 25 years |  |  |  |  |  |  |  |  |  |
Number of business acquisitions completed | 3 | 4 |  |  | 5 | 1 | 1 | 1 | 1 | 3 | 3 | 1 | 1 | 1

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- Definition Licensing terms maximum in years. + References No definition available. + Details
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- Definition Licensing terms minimum in years. + References No definition available. + Details
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- Details
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- Definition The number of businesses acquired by the entity during the period. + References No definition available. + Details
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