Summary Of Significant Accounting Policies (Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Goodwill, Purchase Accounting Adjustments	$ 112
Balance at beginning	76,257
Balance at ending	55,877
Goodwill, Written off Related to Sale of Business Unit	(71,123)
Goodwill, Acquired During Period	50,631
Ecova [Member]
Goodwill, Purchase Accounting Adjustments	112
Balance at beginning	71,011
Balance at ending	0
Goodwill, Written off Related to Sale of Business Unit	(71,123)
Goodwill, Acquired During Period	0
Alaska Electric Light & Power [Member]
Goodwill, Purchase Accounting Adjustments	0
Balance at beginning	0
Balance at ending	50,631
Goodwill, Written off Related to Sale of Business Unit	0
Goodwill, Acquired During Period	50,631
Other Business Segment [Member]
Goodwill, Purchase Accounting Adjustments	0
Balance at beginning	12,979
Balance at ending	12,979
Goodwill, Written off Related to Sale of Business Unit	0
Goodwill, Acquired During Period	0
Accumulated Impairment Losses [Member]
Goodwill, Purchase Accounting Adjustments	0
Balance at beginning	(7,733)
Balance at ending	(7,733)
Goodwill, Written off Related to Sale of Business Unit	0
Goodwill, Acquired During Period	$ 0