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- Definition

Number Of Lease Acres

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- Definition

Number Of Lease Acres Held By Unit

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- Definition

Number Of Lease Acres In Unit / Participating Area

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- Definition

Number Of Miles From Anchorage

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- Definition

Oil and Gas Delivery Commitments and Contracts, Lifted Volume

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- Definition

Oil and Gas Delivery Commitments and Contracts, Lifted Volume during the period

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- Definition

Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

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- Definition

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount recognized as of the acquisition date for the identifiable assets acquired in excess of (less than) the aggregate liabilities assumed.

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- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

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- Definition

Total available amounts expected to be received from each oil producing property.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1207
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- Definition

Total amount of product committed to be supplied under existing contracts or agreements.

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The total amount of regulated operating revenues recognized during the period.

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Beluga River Unit (Narrative) (Details)		3 Months Ended								12 Months Ended
Beluga River Unit (Narrative) (Details)	Feb. 04, 2016 USD ($) a Mcf	Dec. 31, 2017 USD ($) Mcf	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) Mcf	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) mi Mcf	Dec. 31, 2016 USD ($) Mcf	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Revenue		$ 62,934,930	$ 49,405,607	$ 51,554,650	$ 60,793,482	$ 57,741,954	$ 45,132,973	$ 44,622,517	$ 50,250,135	$ 224,688,669	$ 197,747,579	$ 216,421,152
Beluga River Unit [Member]
Business Acquisition [Line Items]
Date of Purchase and Sale Agreement										Feb. 04, 2016
Total purchase price	$ 148,000,000
Cash consideration	$ 44,400,000
Working interest ownership percentage	30.00%	10.00%								10.00%
Number of lease acres \| a	15,500
Number of lease acres in Unit / Participating Area \| a	8,200
Number of lease acres held by Unit \| a	7,300
Number of miles from Anchorage \| mi										35
Acquisition costs						$ 1,500,000					$ 1,500,000
Amount of gas acquired \| Mcf	69,099	8				84				8	84
Revenue										$ 6,600,000	$ 2,800,000
Lifted amount of gas during the period \| Mcf										1,400,000
Lifted amount of gas in proven developed reserves \| Mcf		3,100,000								3,100,000
Remaining amount of gas in proven developed reserves \| Mcf		25,100,000								25,100,000
Municipal Light & Power [Member] \| Beluga River Unit [Member]
Business Acquisition [Line Items]
Working interest ownership percentage	70.00%	56.70%								56.70%
ConocoPhillips (COP) [Member] \| Beluga River Unit [Member]
Business Acquisition [Line Items]
Working interest ownership percentage		33.30%								33.30%
ConocoPhillips (COP) [Member] \| Deep Oil Resources [Member]
Business Acquisition [Line Items]
Working interest ownership percentage	67.00%
Hilcorp Alaska, LLC [Member] \| Beluga River Unit [Member]
Business Acquisition [Line Items]
Working interest ownership percentage		33.30%								33.30%
ENSTAR [Member] \| ConocoPhillips (COP) [Member]
Business Acquisition [Line Items]
Expiration year of Gas Sale and Purchase Agreement										2017