Summary Of Significant Accounting Policies (Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Balance at beginning	$ 76,257us-gaap_Goodwill	$ 75,959us-gaap_Goodwill
Goodwill acquired during the year	52,730us-gaap_GoodwillAcquiredDuringPeriod
Adjustments	112	298
Balance at ending	57,976us-gaap_Goodwill	76,257us-gaap_Goodwill
Goodwill, Written off Related to Sale of Business Unit	(71,123)
Ecova [Member]
Balance at beginning	71,011	70,713
Goodwill acquired during the year	0
Adjustments	112	298
Balance at ending	0	71,011
Goodwill, Written off Related to Sale of Business Unit	(71,123)
Alaska Electric Light & Power [Member]
Balance at beginning	0	0
Goodwill acquired during the year	52,730
Adjustments	0	0
Balance at ending	52,730	0
Goodwill, Written off Related to Sale of Business Unit	0
Other [Member]
Balance at beginning	12,979	12,979
Goodwill acquired during the year	0
Adjustments	0	0
Balance at ending	12,979	12,979
Goodwill, Written off Related to Sale of Business Unit	0
Accumulated Impairment Losses [Member]
Goodwill, Impaired, Accumulated Impairment Loss	(7,733)	(7,733)	(7,733)
Goodwill acquired during the year	0
Adjustments	0	0
Goodwill, Written off Related to Sale of Business Unit	$ 0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 16

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e961-128460

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