Redeemable Noncontrolling Interests And Subsidiary Acquisitions (Narrative) (Details) (USD $)	1 Months Ended	12 Months Ended				1 Months Ended			1 Months Ended
	Jan. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Jan. 31, 1999	Jan. 31, 2012 Ecova [Member]	Nov. 30, 2011 Ecova [Member]	Dec. 31, 2011 LPB Energy Management [Member]	Nov. 30, 2011 Client Relationships [Member] Ecova [Member]	Nov. 30, 2011 Internal Use Software [Member] Ecova [Member]
Business Acquisition [Line Items]
Redemption rights expire date		July 31, 2012
Purchase of shares held by subsidiaries	$ 5,600,000
Cash paid for acquisition							35,600,000	50,300,000
Assets acquired, accounts receivable							2,400,000
Assets acquired, deferred income tax assets							3,700,000
Assets acquired, goodwill							12,900,000
Intangible assets acquired									7,400,000	5,400,000
Estimated amortization period, minimum (in years)										5
Estimated amortization period, maximum (in years)										6
Estimated amortization period (in years)									9
Borrowings under committed credit agreement					145,000,000	25,000,000
Equity infusion from existing shareholders		$ 26,463,000	$ 46,235,000	$ 2,622,000		$ 20,000,000