CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Utility plant:
Utility plant	$ 3,952,681	$ 3,890,423
Less accumulated depreciation and amortization	(1,267,745)	(1,239,865)
Net utility plant	2,684,936	2,650,558
Current assets:
Cash and cash equivalents	84,387	44,555
Receivables:
Customers, net	39,652	44,025
Regulatory balancing accounts	97,820	96,241
Other, net	19,470	20,331
Unbilled revenue, net	33,945	34,069
Materials and supplies at weighted average cost	9,201	8,831
Taxes, prepaid expenses, and other assets	17,925	17,964
Total current assets	302,400	266,016
Other assets:
Regulatory assets	328,336	325,376
Goodwill	31,390	31,842
Other assets	124,405	120,456
Total other assets	484,131	477,674
TOTAL ASSETS	3,471,467	3,394,248
Capitalization:
Common stock, $0.01 par value; 68,000 shares authorized, 50,835 and 50,334 outstanding in 2021 and 2020, respectively	508	503
Additional paid-in capital	471,698	448,632
Retained earnings	457,596	472,209
Total common stockholders’ equity	929,802	921,344
Long-term debt, net	780,951	781,100
Total capitalization	1,710,753	1,702,444
Current liabilities:
Current maturities of long-term debt, net	5,136	5,127
Short-term borrowings	435,000	370,000
Accounts payable	120,549	131,725
Regulatory balancing accounts	34,215	34,636
Accrued interest	14,728	6,178
Accrued expenses and other liabilities	45,838	41,040
Total current liabilities	655,466	588,706
Deferred income taxes	275,987	276,032
Pension and postretirement benefits other than pensions	111,926	115,581
Regulatory liabilities and other	251,851	247,810
Advances for construction	197,715	195,625
Contributions in aid of construction	267,769	268,050
Commitments and contingencies (Note 10)
TOTAL CAPITALIZATION AND LIABILITIES	$ 3,471,467	$ 3,394,248