Derivative and Hedging Instruments (Details-1) (USD $) In Thousands, unless otherwise specified						12 Months Ended										12 Months Ended
	Dec. 31, 2013 Other Current Assets [Member]	Dec. 31, 2012 Other Current Assets [Member]	Dec. 31, 2011 Other Current Assets [Member]	Dec. 31, 2013 Commodity Contracts and Financial Transimission Rights [Member]	Dec. 31, 2012 Commodity Contracts and Financial Transimission Rights [Member]	Dec. 31, 2013 Commodity Derivative Contracts [Member] MWh Dth	Dec. 31, 2012 Commodity Derivative Contracts [Member] MWh Dth	Dec. 31, 2013 Commodity Derivative Contracts [Member] Other Current Assets [Member]	Dec. 31, 2012 Commodity Derivative Contracts [Member] Other Current Assets [Member]	Dec. 31, 2013 Commodity Derivative Contracts [Member] Other Deferred Charges [Member]	Dec. 31, 2012 Commodity Derivative Contracts [Member] Other Deferred Charges [Member]	Dec. 31, 2013 Commodity Derivative Contracts [Member] Derivative Liability (Current) [Member]	Dec. 31, 2012 Commodity Derivative Contracts [Member] Derivative Liability (Current) [Member]	Dec. 31, 2013 Commodity Derivative Contracts [Member] Derivative Liability (Long-term) [Member]	Dec. 31, 2012 Commodity Derivative Contracts [Member] Derivative Liability (Long-term) [Member]	Dec. 31, 2013 Energy Related Commodity Contract [Member] Cash Flow Hedging [Member]	Dec. 31, 2013 Financial Transmission Rights [Member] MW	Dec. 31, 2012 Financial Transmission Rights [Member] MW	Dec. 31, 2013 Financial Transmission Rights [Member] Other Current Assets [Member]	Dec. 31, 2012 Financial Transmission Rights [Member] Other Current Assets [Member]	Dec. 31, 2013 Financial Transmission Rights [Member] Derivative Liability (Current) [Member]	Dec. 31, 2012 Financial Transmission Rights [Member] Derivative Liability (Current) [Member]	Dec. 31, 2013 Ten-year PPA [Member]	Dec. 31, 2012 Ten-year PPA [Member]	Dec. 31, 2013 Ten-year PPA [Member] Derivative Liability (Current) [Member]	Dec. 31, 2012 Ten-year PPA [Member] Derivative Liability (Current) [Member]	Dec. 31, 2013 Ten-year PPA [Member] Derivative Liability (Long-term) [Member]	Dec. 31, 2012 Ten-year PPA [Member] Derivative Liability (Long-term) [Member]
Derivatives Fair Value [Line Items]
Maximum term of derivative hedging contract																4 years
Gross Notional Volume of Open Derivatives
Notional amount, energy measure (in MWh)						458,660	444,650
Notional amount, decatherm measure (in Dth)						3,750,000	1,980,000
Notional amount, power measure (in MW)																	1,984	2,670
Derivative Fair Values [Abstract]
Derivative fair value, net	$ 411	$ 574	$ 1,604	$ 1,800	$ 300																		$ (65,700)	$ (72,600)
Derivative fair value, gross asset						1,523	460	1,356	365	167	95						363	206	363	206
Derivative fair value, gross liability						$ 99	$ 405					$ 51	$ 394	$ 48	$ 11						$ 0	$ 0	$ 65,680	$ 72,590	$ 7,750	$ 9,270	$ 57,930	$ 63,320