Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income	$ 46,184	$ 44,800
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	45,494	44,286
Deferred income taxes and investment tax credits	(2,517)	(3,390)
Changes in regulatory assets and liabilities	7,873	2,833
Pension and postretirement benefit plan expense	7,266	7,367
Contributions to pension and postretirement benefit plans	(997)	(918)
Earnings of unconsolidated equity-method investments	(2,308)	(2,317)
Distributions from equity-method investments	2,480	2,550
Allowance for equity funds used during construction	(9,123)	(7,769)
Other non-cash adjustments to net income, net	4,083	3,238
Change in:
Accounts receivable	(4,257)	(3,451)
Accounts payable	(44,989)	(42,219)
Taxes accrued/receivable	16,377	17,156
Other current assets	14,521	19,403
Other current liabilities	13,894	2,425
Other assets	(3,672)	(2,234)
Other liabilities	2,690	1,902
Net cash provided by operating activities	92,999	83,662
Investing Activities:
Additions to utility plant	(102,535)	(77,293)
Payments received from transmission project joint funding partners	1,299	1,096
Investments in affordable housing	(2,628)	(5,335)
Distributions from equity-method investments, return of investment	2,920	750
Purchases of equity securities	(20,988)	(171)
Purchases of held-to-maturity securities	(29,692)	0
Proceeds from the sale of equity securities	51,288	1,557
Purchases of short-term investments	0	(25,000)
Maturities of short-term investments	0	25,000
Other	2,049	47
Net cash used in investing activities	(98,287)	(79,349)
Financing Activities:
Issuance of long-term debt	50,000	0
Dividends on common stock	(38,371)	(36,379)
Tax withholdings on net settlements of share-based awards	2,958	3,026
Debt issuance costs and other	(76)	(17)
Net cash provided by (used in) financing activities	8,595	(39,422)
Net increase (decrease) in cash and cash equivalents	3,307	(35,109)
Cash and cash equivalents at beginning of the period	215,243	275,116
Cash and cash equivalents at end of the period	218,550	240,007
Supplemental Disclosure of Cash Flow Information:
Interest (net of amount capitalized)	25,306	25,306
Non-cash investing activities:
Additions to property, plant and equipment in accounts payable	$ 52,137	$ 27,910