CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Utility plant:
Utility plant	$ 2,190,573	$ 2,096,363
Less accumulated depreciation and amortization	(685,351)	(639,307)
Net utility plant	1,505,222	1,457,056
Current assets:
Cash and cash equivalents	48,847	38,790
Receivables: net of allowance for doubtful accounts of $815 as of September 30, 2013 and $714 as of December 31, 2012
Customers	42,979	29,958
Regulatory balancing accounts	27,047	34,020
Other	9,802	11,943
Unbilled revenue	25,815	15,394
Materials and supplies at weighted average cost	5,689	5,874
Taxes, prepaid expenses and other assets	10,373	10,585
Total current assets	170,552	146,564
Other assets:
Regulatory assets	354,879	344,419
Goodwill	2,615	2,615
Other assets	50,165	45,270
Total other assets	407,659	392,304
Total assets	2,083,433	1,995,924
Capitalization:
Common stock, $.01 par value; 68,000,000 shares authorized, 47,739,024 and 41,908,218 outstanding in 2013 and 2012, respectively	477	419
Additional paid-in capital	327,890	221,013
Retained earnings	271,887	252,280
Total common stockholders' equity	600,254	473,712
Long-term debt, less current maturities	430,227	434,467
Total capitalization	1,030,481	908,179
Current liabilities:
Current maturities of long-term debt	48,013	46,783
Short-term borrowings	11,515	89,475
Accounts payable	60,414	47,199
Regulatory balancing accounts	1,699	5,018
Accrued interest	10,656	4,705
Accrued expenses and other liabilities	64,716	49,887
Total current liabilities	197,013	243,067
Unamortized investment tax credits	2,180	2,180
Deferred income taxes, net	168,091	158,846
Pension and postretirement benefits other than pensions	247,335	244,901
Regulatory and other liabilities	91,185	92,593
Advances for construction	184,879	187,584
Contributions in aid of construction	162,269	158,574
Commitments and contingencies
Total capitalization and liabilities	$ 2,083,433	$ 1,995,924