Capitalization (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
First Mortgage Bonds	$ 87,471	$ 91,938
SRF Bonds	625	708
Fair Value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
First Mortgage Bonds	80,193	93,556
SRF Bonds	$ 628	$ 712