Regulatory Matters (Details) (USD $)	1 Months Ended		3 Months Ended								12 Months Ended																	12 Months Ended		12 Months Ended
	Dec. 31, 2012	Nov. 30, 2012	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 MW MWh item	Dec. 31, 2011	Dec. 31, 2010	Sep. 28, 2012	May 14, 2012	Feb. 06, 2013 Retail Customers [Member]	Nov. 12, 2012 Retail Customers [Member]	May 14, 2012 Retail Customers [Member]	Nov. 12, 2012 Homer Electric Association, Inc. [Member]	Nov. 12, 2012 Matanuska Electric Association, Inc. [Member]	Nov. 12, 2012 Seward [Member]	May 14, 2012 Wholesale Customers [Member]	Dec. 31, 2012 2012 Series A First Mortgage Bonds [Member]	Dec. 31, 2012 2012 Series A First Mortgage Bonds [Member] Tranche A [Member]	Dec. 31, 2012 2012 Series A First Mortgage Bonds [Member] Tranche B [Member]	Dec. 31, 2012 2012 Series A First Mortgage Bonds [Member] Tranche C [Member]	Feb. 06, 2013 Minimum [Member] Wholesale Customers [Member]	Dec. 31, 2012 Minimum [Member] 2012 Series A First Mortgage Bonds [Member]	Feb. 06, 2013 Maximum [Member] Wholesale Customers [Member]	Dec. 31, 2012 Maximum [Member] 2012 Series A First Mortgage Bonds [Member]	Dec. 31, 2013 Forecast [Member]
Regulatory Matters [Line Items]
Recommended life of SPP project											35 years
Purchase power agreement, years	25 years		25 years								25 years
Number of wind turbine generators											11
Capacity of wind turbine generators											1.6
Total capacity of wind turbine generators											17.6
Expected annual output of wind turbine generators											50,000
Grant received from State of Alaska											$ 25,000,000
Construction expenditures against state grant											20,300,000	3,200,000
Bonds, face value																								75,000,000	125,000,000	50,000,000
Bonds, interest rate																								4.01%	4.41%	4.78%
Bonds, amortization period																												20 years		30 years
Regulatory asset																							1,100,000
Request for regulatory asset		1,800,000
Operating revenues			74,483,455	62,675,511	58,631,729	71,180,773	76,828,268	68,778,352	68,517,526	69,494,223	266,971,468	283,618,369	258,325,345																		2,000,000
Proposed increase in base rate revenue	30,000,000
Proposed percentage increase in base rate revenue	26
Base rate revenue for proposed rate increase	115,000,000
Increase (decrease) in system demand and energy rate														(1.70%)	(0.10%)	6.00%	(1.70%)	1.30%	(2.10%)	(1.90%)	1.60%	(2.90%)					4.00%		7.00%
Increase (decrease) in system demand and energy rate, amount														$ (1,900,000)	$ (800,000)