Redeemable Noncontrolling Interests And Subsidiary Acquisitions (Narrative) (Details) (USD $)	3 Months Ended		1 Months Ended	12 Months Ended			1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Jan. 31, 2012 Ecova [Member]	Dec. 31, 2011 Prenova [Member] Y	Nov. 30, 2011 Prenova [Member]	Jan. 31, 2012 LPB Energy Management [Member]	Jan. 31, 2012 Client Backlog [Member] LPB Energy Management [Member]	Jan. 31, 2012 Client Relationships [Member] LPB Energy Management [Member] Y	Jan. 31, 2012 Internal Use Software [Member] LPB Energy Management [Member]
Business Acquisition [Line Items]
Redemption rights expiration date	July 31, 2012
Cash paid for acquisition					$ 35,600,000	$ 50,600,000
Assets acquired, accounts receivable						2,500,000
Assets acquired, goodwill						33,500,000
Intangible assets acquired							8,200,000	4,800,000	2,500,000
Estimated amortization period, minimum (in years)									3
Estimated amortization period, maximum (in years)									4
Estimated amortization period (in years)				9			3	10
Borrowings under committed credit agreement			25,000,000
Equity infusion from existing shareholders	$ 1,437,000	$ 8,458,000	$ 20,000,000