Segment Information Major Customers (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2012 customers	Sep. 30, 2011 customers	Sep. 30, 2012 customers	Sep. 30, 2011 customers
Revenue, Major Customer [Line Items]
Major Customers Percentage Revenue Threshold	10.00%	10.00%	10.00%	10.00%
Entity-Wide Revenue, Major Customer, Percentage			10.00%
Number Of Major Customers	0	0	1	0
Energy Operating Segment [Member]
Revenue, Major Customer [Line Items]
Major Customers Percentage Revenue Threshold	10.00%	10.00%	10.00%	10.00%
Number Of Major Customers	1	1	1	1
Segment Revenue, Percentage, by Each Major Customer	11.00%	10.00%	13.00%	11.00%
Water Operating Segment [Member]
Revenue, Major Customer [Line Items]
Major Customers Percentage Revenue Threshold	10.00%	10.00%	10.00%	10.00%
Number Of Major Customers	0	0	0	0