Long-Term Debt Long-Term Debt (Snettisham Capital Lease Obligation) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Capital Leased Assets [Line Items]
Utilities Operating Expense, Products and Services	$ 209,560	$ 220,497
Alaska Electric Light & Power [Member]
Capital Leased Assets [Line Items]
Utilities Operating Expense, Products and Services	2,900	0
Capital Leased Assets, Gross	71,007		71,007
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	2,731		1,821
Alaska Electric Light & Power [Member] | Capital Lease Obligations [Member]
Capital Leased Assets [Line Items]
Capital Leases Future Minimum Payments of Principal Remainder Of Fiscal Year	1,673
Capital Lease Obligations	69,398
Capital Leases Future Minimum Payments of Principal Year Two	2,350
Capital Leases Future Minimum Payments of Principal Year Three	2,480
Capital Leases Future Minimum Payments of Principal Year Four	2,615
Capital Leases Future Minimum Payments of Principal Year Five	2,755
Capital Leases Future Minimum Payments of Principal Thereafter	57,525
Capital Leases Future Minimum Payments of Interest Remainder Of Fiscal Year	2,767
Capital Leases Future Minimum Payments of Interest Due in Two Years	3,567
Capital Leases Future Minimum Payments of Interest Due in Three Years	3,438
Capital Leases Future Minimum Payments of Interest Due in Four Years	3,305
Capital Leases Future Minimum Payments of Interest Due in Five Years	3,165
Capital Leases Future Minimum Payments of Interest Due Thereafter	25,364
Capital Leases Future Minimum Payments of Interest Due	41,606
Capital Leases, Future Minimum Payments, Remainder of Fiscal Year	4,440
Capital Leases, Future Minimum Payments Due in Two Years	5,917
Capital Leases, Future Minimum Payments Due in Three Years	5,918
Capital Leases, Future Minimum Payments Due in Four Years	5,920
Capital Leases, Future Minimum Payments Due in Five Years	5,920
Capital Leases, Future Minimum Payments Due Thereafter	82,889
Capital Leases, Future Minimum Payments Due	111,004
Alaska Electric Light & Power [Member] | Reported Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member] | Capital Lease Obligations [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	69,398		69,955
Capital Lease Interest [Member] | Alaska Electric Light & Power [Member]
Capital Leased Assets [Line Items]
Utilities Operating Expense, Products and Services	923	0
Capital Lease Amortization [Member] | Alaska Electric Light & Power [Member]
Capital Leased Assets [Line Items]
Utilities Operating Expense, Products and Services	$ 910	$ 0