CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net income	$ 31,417	$ 22,419
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	30,987	27,425
Deferred income taxes	1,843	11,348
Amortization of investment tax credits	(131)	(131)
Allowance for equity funds used during construction	(1,855)	(1,287)
Net derivative losses	154	166
Other, net	511	0
Changes in operating assets and liabilities:
Accounts receivable	(9,504)	(10,867)
Accrued unbilled revenues	12,026	12,986
Inventories	6,103	4,806
Other current assets	5,854	4,305
Accounts payable	(15,873)	19,809
Net regulatory assets and liabilities	10,518	656
Other current liabilities	(1,837)	(9,158)
Pension and other employee benefit obligations	(9,200)	(8,860)
Change in other noncurrent assets	157	(294)
Change in other noncurrent liabilities	(474)	(800)
Net cash provided by operating activities	60,696	72,523
Investing activities
Utility capital/construction expenditures	(58,488)	(47,999)
Allowance for equity funds used during construction	1,855	1,287
Other, net	(197)	(159)
Net cash used in investing activities	(56,830)	(46,871)
Financing activities
Proceeds from (repayments of) short-term borrowings, net	11,000	(27,000)
Repayments of long-term debt	(6)	(13)
Capital contributions from parent	3,326	12,282
Dividends paid to parent	(15,481)	(10,729)
Other, net	(331)	(70)
Net cash used in financing activities	(1,492)	(25,530)
Net change in cash and cash equivalents	2,374	122
Cash and cash equivalents at beginning of period	1,403	1,546
Cash and cash equivalents at end of period	3,777	1,668
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(5,751)	(6,020)
Cash paid for income taxes, net	(7,038)	(11,489)
Supplemental disclosure of non-cash investing transactions:
Property, plant and equipment additions in accounts payable	$ 21,757	$ 15,150