Derivatives And Risk Management (Energy Commodity Derivatives) (Details)	12 Months Ended
	Dec. 31, 2013 frequency
Sales [Member] | Electric Derivative [Member] | Physical [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	509,000	[1]
2015	222,000	[1]
2016	287,000	[1]
2017	286,000	[1]
2018	286,000	[1]
Thereafter	158,000	[1]
Sales [Member] | Electric Derivative [Member] | Financial [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	3,116,000	[1]
2015	2,542,000	[1]
2016	1,634,000	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Sales [Member] | Gas Derivative [Member] | Physical [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	3,504,000	[1]
2015	0	[1]
2016	0	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Sales [Member] | Gas Derivative [Member] | Financial [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	105,433,000	[1]
2015	46,840,000	[1]
2016	21,320,000	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Purchase [Member] | Electric Derivative [Member] | Physical [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	769,000	[1]
2015	397,000	[1]
2016	397,000	[1]
2017	397,000	[1]
2018	397,000	[1]
Thereafter	235,000	[1]
Purchase [Member] | Electric Derivative [Member] | Financial [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	2,156,000	[1]
2015	1,043,000	[1]
2016	0	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Purchase [Member] | Gas Derivative [Member] | Physical [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	29,642,000	[1]
2015	4,973,000	[1]
2016	2,505,000	[1]
2017	675,000	[1]
2018	0	[1]
Thereafter	0	[1]
Purchase [Member] | Gas Derivative [Member] | Financial [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
2014	145,719,000	[1]
2015	73,580,000	[1]
2016	46,150,000	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]

[1] Physical transactions represent commodity transactions where Avista Utilities will take delivery of either electricity or natural gas and financial transactions represent derivative instruments with no physical delivery, such as futures, swaps or options.