CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Utility plant:
Utility plant	$ 2,306,427	$ 2,213,328
Less accumulated depreciation and amortization	(745,742)	(697,497)
Net utility plant	1,560,685	1,515,831
Current assets:
Cash and cash equivalents	29,485	27,506
Receivables:
Customers	37,070	31,468
Regulatory balancing accounts	45,073	30,887
Other	15,759	18,700
Unbilled revenue	29,489	17,034
Materials and supplies at weighted average cost	5,912	5,571
Taxes, prepaid expenses and other assets	14,490	8,324
Total current assets	177,278	139,490
Other assets:
Regulatory assets	277,476	251,681
Goodwill	2,615	2,615
Other assets	51,026	50,238
Total other assets	331,117	304,534
Total assets	2,069,080	1,959,855
Capitalization:
Common stock, $.01 par value; 68,000,000 shares authorized, 47,806,000 and 47,741,000 outstanding in 2014 and 2013, respectively	478	477
Additional paid-in capital	329,840	328,364
Retained earnings	291,964	269,915
Total common stockholders' equity	622,282	598,756
Long-term debt, less current maturities	422,825	426,142
Total capitalization	1,045,107	1,024,898
Current liabilities:
Current maturities of long-term debt	6,619	7,908
Short-term borrowings	61,715	46,815
Accounts payable	71,867	55,087
Regulatory balancing accounts	6,791	1,827
Accrued interest	9,748	4,245
Accrued expenses and other liabilities	58,674	50,702
Total current liabilities	215,414	166,584
Unamortized investment tax credits	2,106	2,106
Deferred income taxes, net	210,357	183,245
Pension and postretirement benefits other than pensions	153,085	145,451
Regulatory and other liabilities	91,713	86,455
Advances for construction	182,172	183,393
Contributions in aid of construction	169,126	167,723
Commitments and contingencies (Note 10)
Total capitalization and liabilities	$ 2,069,080	$ 1,959,855