Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating Activities:
Net income	$ 110,773	$ 115,074
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	81,351	88,889
Deferred income taxes and investment tax credits	(16,953)	(6,169)
Changes in regulatory assets and liabilities	8,658	9,311
Pension and postretirement benefit plan expense	14,484	14,534
Contributions to pension and postretirement benefit plans	(12,122)	(11,957)
Earnings of unconsolidated equity-method investments	(4,596)	(4,630)
Distributions from equity-method investments	4,265	4,100
Allowance for equity funds used during construction	(18,410)	(15,564)
Other non-cash adjustments to net income, net	5,953	4,428
Change in:
Accounts receivable	(13,045)	(15,241)
Accounts payable	(23,439)	2,620
Taxes accrued/receivable	31,253	25,728
Other current assets	(17,044)	(48,206)
Other current liabilities	7,882	5,658
Other assets	(7,590)	(3,285)
Other liabilities	4,535	1,905
Net cash provided by operating activities	155,955	167,195
Investing Activities:
Additions to utility plant	(194,094)	(128,265)
Payments received from transmission project joint funding partners	5,531	2,253
Investments in affordable housing	(2,665)	(10,164)
Distributions from equity-method investments, return of investment	10,335	0
Purchases of equity securities	(27,942)	(392)
Purchases of held-to-maturity securities	(29,692)	0
Proceeds from the sale of equity securities	52,833	3,197
Purchases of short-term investments	(25,000)	(25,000)
Maturities of short-term investments	0	50,000
Other	6,767	1,347
Net cash used in investing activities	(203,927)	(107,024)
Financing Activities:
Issuance of long-term debt	150,000	0
Dividends on common stock	(76,339)	(72,285)
Tax withholdings on net settlements of share-based awards	2,958	3,026
Debt issuance costs and other	(88)	(11)
Net cash provided by (used in) financing activities	70,615	(75,322)
Net increase (decrease) in cash and cash equivalents	22,643	(15,151)
Cash and cash equivalents at beginning of the period	215,243	275,116
Cash and cash equivalents at end of the period	237,886	259,965
Supplemental Disclosure of Cash Flow Information:
Interest (net of amount capitalized)	41,657	41,626
Non-cash investing activities:
Additions to property, plant and equipment in accounts payable	$ 70,063	$ 30,984