Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Utility plant:
Land	$ 40,283	$ 42,264
Depreciable plant and equipment	2,522,174	2,301,841
Construction work in progress	132,957	141,622
Intangible assets	21,925	21,219
Total utility plant	2,717,339	2,506,946
Less accumulated depreciation and amortization	(858,062)	(805,178)
Net utility plant	1,859,277	1,701,768
Current assets:
Cash and cash equivalents	25,492	8,837
Receivables: net of allowance for doubtful accounts of $830 and $730 in 2016 and 2015, respectively
Customers	30,305	31,512
Regulatory balancing accounts	30,332	35,052
Other	17,158	14,760
Unbilled revenue	25,228	23,181
Materials and supplies at weighted average cost	6,292	6,339
Taxes, prepaid expenses, and other assets	7,262	7,897
Total current assets	142,069	127,578
Other assets:
Regulatory assets	355,930	361,893
Goodwill	2,615	2,615
Other	51,854	47,399
Total other assets	410,399	411,907
TOTAL ASSETS	2,411,745	2,241,253
Capitalization:
Common stock, $0.01 par value; 68,000 shares authorized, 47,965 and 47,875 outstanding in 2016 and 2015, respectively	480	479
Additional paid-in capital	334,856	333,135
Retained earnings	324,135	308,541
Total common stockholders' equity	659,471	642,155
Long-term debt, less current maturities	531,745	508,002
Total capitalization	1,191,216	1,150,157
Current liabilities:
Current maturities of long-term debt	26,208	6,043
Short-term borrowings	97,100	33,615
Accounts payable	77,813	66,380
Regulatory balancing accounts	4,759	2,227
Accrued other taxes	3,629	3,417
Accrued interest	5,661	5,088
Other accrued liabilities	35,060	31,128
Total current liabilities	250,230	147,898
Unamortized investment tax credits	1,798	1,872
Deferred income taxes	298,924	264,897
Regulatory liabilities	38,735	35,264
Pension and postretirement benefits other than pensions	222,691	236,266
Advances for construction	182,448	180,172
Contributions in aid of construction	180,790	177,577
Other long-term liabilities	44,913	47,150
Commitments and contingencies	0	0
TOTAL CAPITALIZATION AND LIABILITIES	$ 2,411,745	$ 2,241,253