CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net income	$ 69,135	$ 74,636	$ 70,642
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	99,824	92,656	80,875
Deferred income taxes	37,368	45,833	45,396
Amortization of investment tax credits	(523)	(528)	(527)
Allowance for equity funds used during construction	(4,277)	(7,253)	(7,060)
Loss on Monticello life cycle management/extended power uprate project	0	5,237	0
Provision for bad debts	3,730	3,947	4,431
Net derivative losses	160	482	10
Other	(623)	0	0
Changes in operating assets and liabilities:
Accounts receivable	(1,383)	71	(5,558)
Accrued unbilled revenues	(5,940)	5,869	(1,933)
Inventories	3,250	3,126	(3,210)
Other current assets	(1,191)	7,135	(3,501)
Accounts payable	10,632	(7,626)	2,936
Net regulatory assets and liabilities	(18,601)	(27,114)	(34,697)
Other current liabilities	14,036	5,147	(911)
Pension and other employee benefit obligations	(6,197)	(3,177)	(6,134)
Change in other noncurrent assets	(718)	209	(113)
Change in other noncurrent liabilities	2,050	716	2,534
Net cash provided by operating activities	200,732	199,366	143,180
Investing activities
Utility capital/construction expenditures	(204,427)	(251,797)	(288,209)
Allowance for equity funds used during construction	4,277	7,253	7,060
Other, net	1,198	(224)	(166)
Net cash used in investing activities	(198,952)	(244,768)	(281,315)
Financing activities
Proceeds from (repayments of) short-term borrowings, net	50,000	(68,000)	10,000
Proceeds from notes payable to affiliates	0	0	30
Proceeds from issuance of long-term debt	0	97,969	98,534
Repayments of long-term debt	(93)	(87)	(107)
Capital contributions from parent	1,935	69,243	73,432
Dividends paid to parent	(53,100)	(53,929)	(43,818)
Other, net	(55)	0	0
Net cash (used in) provided by financing activities	(1,313)	45,196	138,071
Net change in cash and cash equivalents	467	(206)	(64)
Cash and cash equivalents at beginning of period	1,079	1,285	1,349
Cash and cash equivalents at end of period	1,546	1,079	1,285
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(30,878)	(27,491)	(24,442)
Cash received for income taxes, net	5,873	5,762	3,474
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 16,172	$ 16,729	$ 35,267