Segment Information Major Customers (Details)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue, Major Customer [Line Items]
Segment Reporting, Disclosure of Major Customers	0	0	1
Energy Operating Segment [Member]
Revenue, Major Customer [Line Items]
Major Customers Percentage Revenue Threshold	10.00%	10.00%	10.00%
Number Of Major Customers	1	1	2
Percentage of total company revenue represented by one customer			11.00%
Water Operating Segment [Member]
Revenue, Major Customer [Line Items]
Major Customers Percentage Revenue Threshold	10.00%	10.00%	10.00%
Number Of Major Customers	0	0	0

Disclosure of the extent of enterprise reliance on its major customers. For example, includes revenues from transactions with a single external customer amounting to 10 percent or more of the entity's revenues, the total amount of revenues from each such customer, and the identity of the segment or segments reporting the revenues. A group of entities that the entity knows to be under common control generally will be considered a single customer for inclusion in this item. The federal government, a state government, a local government (for example, a county or municipality), or a foreign government each will generally be considered as a single customer for inclusion in this item.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 39

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration