Consolidated Statements Of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Assignable margins	$ 5,813,856	$ 6,502,852	$ 6,515,545
Adjustments to reconcile assignable margins to net cash provided by operating activities:
Depreciation and amortization	36,233,414	35,652,086	40,179,181
Amortization and depreciation cleared to operating expenses	4,988,068	4,390,385	5,777,628
Allowance for funds used during construction	(188,111)	(142,881)	(163,151)
Write off of inventory, deferred charges and projects	997,301	691,035	974,062
Other	248,482	(220,496)	56,250
(Increase) decrease in assets:
Accounts receivable, net	(4,926,631)	6,866,956	6,879,762
Materials and supplies	(850,493)	(1,070,896)	(1,197,127)
Fuel stock	741,865	2,588,532	3,377,775
Prepayments	59,275	712,422	(315,316)
Other assets	(71,144)	215,738	978,338
Deferred charges	(10,374,429)	(405,746)	(1,050,505)
Increase (decrease) in liabilities:
Accounts payable	750,538	(270,416)	(420,041)
Consumer deposits	206,901	86,424	62,702
Fuel cost over-recovery	(1,311,023)	3,673,688	(173,620)
Accrued interest	(42,212)	(276,028)	(321,252)
Salaries, wages and benefits	56,092	(287,510)	(385,047)
Fuel	1,342,028	(6,195,299)	(3,696,976)
Other current liabilities	(1,051,220)	(290,715)	1,653,424
Deferred liabilities	(128,221)	(123,695)	34,668
Net cash provided by operating activities	32,494,336	52,096,436	58,766,300
Cash flows from investing activities:
Return of capital from investment in associated organizations	319,233	352,420	351,162
Investment in restricted cash equivalents	(1,398)	(1,141)	(142)
Investment in marketable securitiesand investments-other	(10,580,000)	0	(217,817)
Investment in Beluga River Unit	(44,403,922)	0	0
Proceeds from restricted cash equivalents	1,140,343	0	0
Proceeds from the sale of marketable securities	0	0	10,522,620
Proceeds from capital grants	1,021,929	2,395,331	6,960,143
Extension and replacement of plant	(36,984,892)	(35,094,355)	(30,303,133)
Net cash used in investing activities	(89,488,707)	(32,347,745)	(12,687,167)
Cash flows from financing activities:
Payments for debt issue costs	(277,155)	0	0
Net increase (decrease) in short-term obligations	48,200,000	(1,000,000)	(9,000,000)
Proceeds from long-term obligations	45,600,000	0	0
Repayments of long-term obligations	(48,181,832)	(23,889,777)	(24,682,812)
Memberships and donations received	1,329,489	357,365	(255,730)
Retirement of patronage capital and estate payments	(4,378,853)	(182,352)	(4,114,541)
Net receipts on consumer advances for construction	3,748,738	4,228,030	3,991,749
Net cash provided by (used in) financing activities	46,040,387	(20,486,734)	(34,061,334)
Net change in cash and cash equivalents	(10,953,984)	(738,043)	12,017,799
Cash and cash equivalents at beginning of period	15,626,919	16,364,962	4,347,163
Cash and cash equivalents at end of period	4,672,935	15,626,919	16,364,962
Supplemental disclosure of non-cash investing and financing activities:
Cost of removal obligation	3,008,808	1,366,318	3,565,605
Asset retirement obligation assumed upon BRU acquisition	3,523,409	0	0
Extension and replacement of plant included in accounts payable	1,915,033	2,582,947	2,382,117
Patronage capital retired and included in other current liabilities	0	2,105,440	2,572,670
Supplemental disclosure of cash flow information - interest expense paid, net of amounts capitalized	$ 20,220,317	$ 21,891,308	$ 21,835,216