Commitments and Contingencies, Asset Retirement Obligations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	$ 3,036	[1],[2]	$ 424	[1]
Liabilities recognized	0		1,962
Liabilities settled	0		0
Accretion	84		17
Revisions to prior estimates	(267)		633
Ending balance	2,853	[1],[2]	3,036	[1],[2]
Electric Plant Steam Production Asbestos
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	1,962	[2]	0
Liabilities recognized	0		1,962
Accretion	43		0
Revisions to prior estimates	0		0
Ending balance	2,005	[2]	1,962	[2]
Electric Plant Steam and Other Production Ash Containment
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	125	[2]	120
Liabilities recognized	0		0
Accretion	12		5
Revisions to prior estimates	224		0
Ending balance	361	[2]	125	[2]
Electric Plant Electric Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	13	[2]	13
Liabilities recognized	0		0
Accretion	1		0
Revisions to prior estimates	22		0
Ending balance	36	[2]	13	[2]
Electric Plant Other
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	826	[2]	186
Liabilities recognized	0		0
Accretion	20		7
Revisions to prior estimates	(557)		633
Ending balance	289	[2]	826	[2]
Natural Gas Plant Gas Transmission and Distribution
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	75	[2]	71
Liabilities recognized	0		0
Accretion	5		4
Revisions to prior estimates	(5)		0
Ending balance	75	[2]	75	[2]
Common and Other Property Common Miscellaneous
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	35	[2]	34
Liabilities recognized	0		0
Accretion	3		1
Revisions to prior estimates	49		0
Ending balance	$ 87	[2]	$ 35	[2]

[1] Included in the other long-term liabilities balance in the consolidated balance sheets.

[2] There were no ARO liabilities settled during the 12 months ended Dec. 31, 2013 or 2012.