Commitments And Contingencies (Narrative) (Details) Mcf in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) $ / Mcfe agreement Mcf	Dec. 31, 2016 USD ($)
Other Commitments [Line Items]
Contingency accruals	$ 0
Patronage capital payable, noncurrent	10,798,077	$ 12,008,499
Other current liabilities	8,146,356	3,234,586
Homer Electric Association, Inc. [Member]
Other Commitments [Line Items]
Patronage capital payable, noncurrent	5,900,000	7,900,000
Patronage capital, annual retirements	2,000,000
Other current liabilities	2,000,000
Matanuska Electric Association, Inc. [Member]
Other Commitments [Line Items]
Patronage capital payable, noncurrent	4,900,000	$ 4,100,000
Retirement payments	$ 800,000
Hilcorp Alaska - Cook Inlet [Member]
Other Commitments [Line Items]
Commencement date of long term contract for purchase of gas supply	Jan. 01, 2015
Expiration date of long term contract for purchase of gas supply	Mar. 31, 2018
Estimated amount of gas under contract | Mcf	60.0
Percentage Of Met Natural Gas Needs	100.00%
Initial extension date of long term contract for purchase of gas supply	Mar. 31, 2019
Subsequent extension date of long term contract for purchase of gas supply	Mar. 31, 2023
Furie Operating Alaska, LLC Purchase Commitment [Member]
Other Commitments [Line Items]
Term of purchase commitment	16 years
Commencement date of long term contract for purchase of gas supply	Apr. 01, 2023
Expiration date of long term contract for purchase of gas supply	Mar. 31, 2033
Approximate annual volume | Mcf	1.8
Minimum [Member] | Furie Operating Alaska, LLC Purchase Commitment [Member]
Other Commitments [Line Items]
Price per Mcf | $ / Mcfe	7.16
Percentage Of Met Natural Gas Needs	20.00%
Maximum [Member] | Furie Operating Alaska, LLC Purchase Commitment [Member]
Other Commitments [Line Items]
Price per Mcf | $ / Mcfe	7.98
Percentage Of Met Natural Gas Needs	25.00%
International Brotherhood of Electrical Workers [Member]
Other Commitments [Line Items]
Percentage of employees belonging to unions	70.00%
Number of collective bargaining agreements | agreement	3
Expiration date of collective bargaining agreements	Jun. 30, 2021
Hotel Employees and Restaurant Employees [Member]
Other Commitments [Line Items]
Number of collective bargaining agreements | agreement	1
Expiration date of collective bargaining agreements	Jun. 30, 2021