Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net income	$ 107,362	$ 136,634
Loss from discontinued operations, net of tax	0	2,343
Income from continuing operations	107,362	138,977
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	51,028	48,590
Deferred financing cost amortization	2,007	1,900
Stock compensation	3,296	2,209
Deferred income taxes	19,602	(25,430)
Employee benefit plans	3,137	3,378
Other adjustments, net	4,428	3,053
Changes in certain operating assets and liabilities:
Materials, supplies and fuel	29,387	31,196
Accounts receivable, unbilled revenues and other operating assets	(15,857)	(25,113)
Accounts payable and other operating liabilities	(41,689)	(71,149)
Regulatory assets - current	13,031	47,903
Regulatory liabilities - current	(1,635)	16,098
Other operating activities, net	1,796	(278)
Net cash provided by operating activities of continuing operations	175,893	171,334
Net cash provided by (used in) operating activities of discontinued operations	0	(1,459)
Net cash provided by operating activities	175,893	169,875
Investing activities:
Property, plant and equipment additions	(144,126)	(69,972)
Purchase of investment	0	(23,500)
Other investing activities	(901)	(261)
Net cash provided by (used in) investing activities of continuing operations	(145,027)	(93,733)
Net cash provided by (used in) investing activities of discontinued operations	0	20,179
Net cash provided by (used in) investing activities	(145,027)	(73,554)
Financing activities:
Dividends paid on common stock	(30,332)	(25,444)
Common stock issued	19,949	372
Net (payments) borrowings of short-term debt	(20,970)	(47,100)
Long-term debt - repayments	(1,436)	(1,436)
Distributions to noncontrolling interest	(4,846)	(5,648)
Other financing activities	(1,657)	(1,400)
Net cash provided by (used in) financing activities	(39,292)	(80,656)
Net change in cash, cash equivalents and restricted cash	(8,426)	15,665
Cash, cash equivalents and restricted cash at beginning of period	24,145	18,240
Cash, cash equivalents and restricted cash at end of period	$ 15,719	$ 33,905