CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Operating Activities:
Net income	$ 82,091	$ 65,877
Non-cash items included in net income:
Depreciation and amortization	111,487	115,752
Deferred income tax provision and investment tax credits	11,085	(8,400)
Power and natural gas cost amortizations (deferrals), net	(21,826)	1,815
Amortization of debt expense	1,571	1,365
Stock-based compensation expense	2,280	2,826
Equity-related AFUDC	(3,346)	(3,271)
Pension and other postretirement benefit expense	14,793	16,481
Other regulatory assets and liabilities and deferred debits and credits	4,008	4,391
Change in decoupling regulatory deferral	2,203	(454)
Gain on sale of investments	(1,764)	(3,231)
Other	(7,653)	9,043
Contributions to defined benefit pension plan	(28,000)	(14,600)
Changes in certain current assets and liabilities:
Accounts and notes receivable	26,284	43,701
Materials and supplies, fuel stock and stored natural gas	(15,328)	(751)
Collateral posted for derivative instruments	(24,102)	(7,209)
Income taxes receivable	23,869	9,106
Other current assets	2,505	(5,704)
Accounts payable	8,111	(29,860)
Other current liabilities	1,795	3,011
Net cash provided by operating activities	190,063	199,888
Investing Activities:
Utility property capital expenditures (excluding equity-related AFUDC)	(213,827)	(189,480)
Issuance of notes receivable	(75)	(4,343)
Equity and property investments	(5,650)	(2,097)
Proceeds from sale of investments	6,806	5,144
Other	1,907	(988)
Net cash used in investing activities	(210,839)	(191,764)
Financing Activities:
Net increase in short-term borrowings	93,000	135,200
Maturity of long-term debt and finance leases	(1,491)	(1,431)
Issuance of common stock, net of issuance costs	15,689	23,890
Cash dividends paid	(58,693)	(54,708)
Other	(2,898)	(4,577)
Net cash provided by financing activities	45,607	98,374
Net increase in cash and cash equivalents	24,831	106,498
Cash and cash equivalents at beginning of period	14,196	9,896
Cash and cash equivalents at end of period	$ 39,027	$ 116,394