Business Acquisitions Business Acquisitions (Prenova and LPB Energy Management) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2011 Prenova [Member]	Jan. 31, 2012 LPB Energy Management [Member]	Dec. 31, 2012 Ecova [Member]	Jan. 31, 2012 Ecova [Member]	Dec. 31, 2013 Business Acquisition, Additional Payment Due in Year Two [Member]	Dec. 31, 2012 Business Acquisition, Additional Payment Due in Year Two [Member]	Jan. 31, 2012 Business Acquisition, Additional Payment Due in Year Two [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				$ 35,700,000	$ 50,600,000
Borrowed Funds					25,000,000
Proceeds from Issuance of Common Stock	4,609,000	29,079,000	26,463,000		20,000,000
Contingent consideration by subsidiary for acquisition	0	375,000	0			300,000	400,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High								$ 1,500,000	$ 1,000,000	$ 500,000