Selected Balance Sheet Data

3 Months Ended

Mar. 31, 2012

Selected Balance Sheet Data [Abstract]

Selected Balance Sheet Data

3.      Selected Balance Sheet Data

(Thousands of Dollars)	March 31, 2012			Dec. 31, 2011
Accounts receivable, net (a)
Accounts receivable	$	51,132		$	56,604
Less allowance for bad debts		(4,644	)		(4,766	)
	$	46,488		$	51,838
Inventories
Materials and supplies	$	6,068		$	5,838
Fuel		9,283			9,335
Natural gas		2,466			10,530
	$	17,817		$	25,703
Property, plant and equipment, net
Electric plant	$	1,704,038		$	1,684,537
Natural gas plant		214,655			213,665
Common and other property		112,213			113,597
Construction work in progress		64,528			54,627
Total property, plant and equipment		2,095,434			2,066,426
Less accumulated depreciation		(871,672	)		(858,728	)
	$	1,223,762		$	1,207,698

(a) Accounts receivable, net includes $51 due from affiliates as of March 31, 2012.