Selected Balance Sheet Data

6 Months Ended

Jun. 30, 2011

Selected Balance Sheet Data [Abstract]

Selected Balance Sheet Data

3. Selected Balance Sheet Data

(Thousands of Dollars)	June 30, 2011			Dec. 31, 2010
Accounts receivable, net
Accounts receivable	$	69,182		$	49,966
Less allowance for bad debts		(4,639	)		(5,095	)
	$	64,543		$	44,871
Inventories
Materials and supplies	$	18,415		$	15,093
Fuel		8,260			14,756
	$	26,675		$	29,849
Property, plant and equipment, net
Electric plant	$	4,028,073		$	3,826,202
Construction work in progress		143,371			221,025
Total property, plant and equipment		4,171,444			4,047,227
Less accumulated depreciation		(1,672,738	)		(1,645,961	)
	$	2,498,706		$	2,401,266