Condensed Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
UTILITY PLANT:
Utility plant in service	$ 4,527,535	$ 4,478,752
Less accumulated depreciation	2,208,567	2,149,994
Utility plant in service - net	2,318,968	2,328,758
Construction work in progress	279,724	207,727
Spare parts inventory	14,428	15,774
Property held for future use	1,002	1,002
Utility plant - net	2,614,122	2,553,261
OTHER ASSETS:
Nonutility property - at cost, less accumulated depreciation	525	528
Other investments	6,094	5,902
Other assets - net	6,619	6,430
CURRENT ASSETS:
Cash and cash equivalents	127,786	19,067
Accounts receivable and unbilled revenue (less allowance for doubtful accounts of $2,011 and $1,982, respectively)	144,624	143,408
Fuel inventories - at average cost	50,909	54,763
Materials and supplies - at average cost	58,443	58,067
Deferred tax asset - current	8,996	11,990
Regulatory assets	5,227	2,409
Prepayments and other current assets	38,396	23,247
Total current assets	434,381	312,951
DEFERRED DEBITS:
Regulatory assets	361,583	369,447
Miscellaneous	48,884	31,976
Total deferred debits	410,467	401,423
TOTAL	3,465,589	3,274,065
Common shareholder's equity:
Paid in capital	168,149	61,468
Accumulated deficit	(22,732)	(13,694)
Total common shareholder's equity	145,417	47,774
Cumulative preferred stock of subsidiary	59,784	59,784
Long-term debt	1,950,537	1,821,713
Total capitalization	2,155,738	1,929,271
CURRENT LIABILITIES:
Short-term debt (Note 5)	50,000	50,000
Accounts payable	98,373	99,966
Accrued expenses	22,658	27,417
Accrued real estate and personal property taxes	18,850	19,224
Regulatory liabilities	19,349	12,436
Accrued interest	30,385	29,691
Customer deposits	26,688	26,241
Other current liabilities	26,239	12,200
Total current liabilities	292,542	277,175
DEFERRED CREDITS AND OTHER LONG-TERM LIABILITIES:
Regulatory liabilities	598,223	585,753
Accumulated deferred income taxes - net	324,959	332,363
Non-current income tax liability	6,867	6,734
Unamortized investment tax credit	5,945	6,661
Accrued pension and other postretirement benefits	38,076	93,680
Asset retirement obligations	42,442	41,381
Miscellaneous	797	1,047
Total deferred credits and other long-term liabilities	1,017,309	1,067,619
COMMITMENTS AND CONTINGENCIES (Note 7)
TOTAL	$ 3,465,589	$ 3,274,065