Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Utility plant:
Land	$ 45,047	$ 44,019
Depreciable plant and equipment	3,235,415	2,950,424
Construction work in progress	245,169	210,260
Intangible assets	24,854	24,743
Total utility plant	3,550,485	3,229,446
Less accumulated depreciation and amortization	(1,144,115)	(996,723)
Net utility plant	2,406,370	2,232,723
Current assets:
Cash and cash equivalents	42,653	47,176
Receivables: net of allowance for doubtful accounts of $771 and $757 in 2019 and 2018, respectively
Customers	32,058	30,037
Regulatory balancing accounts	38,225	42,394
Other	14,187	17,101
Unbilled revenue	34,879	33,427
Materials and supplies at weighted average cost	7,745	6,586
Taxes, prepaid expenses, and other assets	14,965	11,981
Total current assets	184,712	188,702
Other assets:
Regulatory assets	433,322	353,569
Goodwill	2,615	2,615
Other	84,289	60,095
Total other assets	520,226	416,279
TOTAL ASSETS	3,111,308	2,837,704
Capitalization:
Common stock, $0.01 par value; 68,000 shares authorized, 48,532 and 48,065 outstanding in 2019 and 2018, respectively	485	481
Additional paid-in capital	362,275	337,623
Retained earnings	417,146	392,053
Total common stockholders' equity	779,906	730,157
Long-term debt, net	786,754	710,027
Total capitalization	1,566,660	1,440,184
Current liabilities:
Current maturities of long-term debt, net	21,868	104,911
Short-term borrowings	175,100	65,100
Accounts payable	108,463	95,580
Regulatory balancing accounts	4,462	12,213
Accrued other taxes	4,445	4,182
Accrued interest	5,810	5,674
Other accrued liabilities	38,573	33,506
Total current liabilities	358,721	321,166
Unamortized investment tax credits	1,575	1,649
Deferred income taxes	222,590	213,033
Regulatory liabilities	211,413	211,275
Pension and postretirement benefits other than pensions	258,907	193,538
Advances for construction	191,062	186,342
Contributions in aid of construction	241,537	225,270
Other long-term liabilities	58,843	45,247
Commitments and contingencies
TOTAL CAPITALIZATION AND LIABILITIES	$ 3,111,308	$ 2,837,704