v2.4.0.6

Segment Information Depreciation and Amortization, by Segment (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012
Property, Plant and Equipment [Line Items] |  |
Depreciation and amortization | $ 24,757 | $ 27,227
Energy Operating Segment [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Depreciation and amortization | 18,471 | 20,656
Water Operating Segment [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Depreciation and amortization | 6,269 | 6,556
Corporate Unallocated [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Depreciation and amortization | $ 17 | $ 15

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- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References 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=6943989&loc=d3e3602-108585 + Details
Name: | us-gaap_DepreciationDepletionAndAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration