Fair Value (Carrying Value And Estimated Fair Value Of Financial Instruments) (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
Sep. 30, 2015	Dec. 31, 2014
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Capital Lease Obligations	$ 69,331	$ 74,149
Reported Value Measurement [Member] \| Level 2 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	951,000	951,000
Reported Value Measurement [Member] \| Level 3 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	492,000	492,000
Reported Value Measurement [Member] \| Level 3 [Member] \| Nonrecourse Long-Term Debt [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	$ 0	1,431
Estimate of Fair Value Measurement [Member] \| Secured and Unsecured Debt [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Fair Value Inputs, Offered Quotes	$ 100.0
Estimate of Fair Value Measurement [Member] \| Level 2 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	$ 1,088,596	1,118,972
Estimate of Fair Value Measurement [Member] \| Level 3 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	505,343	527,663
Estimate of Fair Value Measurement [Member] \| Level 3 [Member] \| Nonrecourse Long-Term Debt [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	$ 0	1,440
Minimum [Member] \| Estimate of Fair Value Measurement [Member] \| Secured and Unsecured Debt [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Fair Value Inputs, Offered Quotes	$ 73.00
Maximum [Member] \| Estimate of Fair Value Measurement [Member] \| Secured and Unsecured Debt [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Fair Value Inputs, Offered Quotes	$ 125.39
Alaska Electric Light & Power [Member] \| Capital Lease Obligations [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Capital Lease Obligations	$ 64,967
Alaska Electric Light & Power [Member] \| Reported Value Measurement [Member] \| Level 3 [Member] \| Capital Lease Obligations [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Capital Lease Obligations	64,967	69,955
Alaska Electric Light & Power [Member] \| Estimate of Fair Value Measurement [Member] \| Level 3 [Member] \| Capital Lease Obligations [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Capital Lease Obligations	63,869	79,290
Affiliated Entity [Member] \| Reported Value Measurement [Member] \| Level 3 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	51,547	51,547
Affiliated Entity [Member] \| Estimate of Fair Value Measurement [Member] \| Level 3 [Member]
Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]
Long-term debt	$ 37,629	$ 38,582

Fair Value and Carrying Value, by Balance Sheet Grouping [Line Items]

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- Definition

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 7

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- Definition

Price at which a dealer is willing to buy an instrument, used as an input to measure fair value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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