Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Utility plant:
Land	$ 42,264	$ 42,181
Depreciable plant and equipment	2,301,841	2,191,194
Construction work in progress	141,622	90,328
Intangible assets	21,219	18,768
Total utility plant	2,506,946	2,342,471
Less accumulated depreciation and amortization	(805,178)	(752,040)
Net utility plant	1,701,768	1,590,431
Current assets:
Cash and cash equivalents	8,837	19,587
Receivables: net of allowance for doubtful accounts of $730 and $697 in 2015 and 2014, respectively
Customers	31,512	25,803
Regulatory balancing accounts	35,052	53,199
Other	14,760	14,136
Unbilled revenue	23,181	23,740
Materials and supplies at weighted average cost	6,339	6,041
Taxes, prepaid expenses, and other assets	7,897	11,618
Total current assets	127,578	154,124
Other assets:
Regulatory assets	361,893	390,331
Unamortized debt premium and expense	4,842	4,640
Goodwill	2,615	2,615
Other	47,399	45,210
Total other assets	416,749	442,796
ASSETS	2,246,095	2,187,351
Capitalization:
Common stock, $0.01 par value; 68,000 shares authorized, 47,875 and 47,806 outstanding in 2015 and 2014, respectively	479	478
Additional paid-in capital	333,135	330,558
Retained earnings	308,541	295,590
Total common stockholders' equity	642,155	626,626
Long-term debt, less current maturities	512,287	419,233
Total capitalization	1,154,442	1,045,859
Current liabilities:
Current maturities of long-term debt	6,600	6,607
Short-term borrowings	33,615	79,115
Accounts payable	66,380	59,395
Regulatory balancing accounts	2,227	6,126
Accrued other taxes	3,417	4,059
Accrued interest	5,088	4,194
Other accrued liabilities	31,128	58,210
Total current liabilities	148,455	217,706
Unamortized investment tax credits	1,872	2,032
Deferred income taxes	264,897	214,842
Regulatory liabilities	35,264	36,447
Pension and postretirement benefits other than pension	236,266	270,865
Advances for construction	180,172	182,284
Contributions in aid of construction	177,577	170,484
Other long-term liabilities	47,150	46,832
Commitments and contingencies	0	0
CAPITALIZATION AND LIABILITIES	$ 2,246,095	$ 2,187,351