Selected Balance Sheet Data

6 Months Ended

Jun. 30, 2014

Balance Sheet Related Disclosures [Abstract]

Selected Balance Sheet Data

Selected Balance Sheet Data

(Thousands of Dollars)	June 30, 2014			Dec. 31, 2013
Accounts receivable, net
Accounts receivable	$	97,260		$	76,426
Less allowance for bad debts	(5,536		)	(5,475		)
	$	91,724		$	70,951

(Thousands of Dollars)	June 30, 2014		Dec. 31, 2013
Inventories
Materials and supplies	$	24,299	$	21,600
Fuel	10,817		15,538
	$	35,116	$	37,138

(Thousands of Dollars)	June 30, 2014			Dec. 31, 2013
Property, plant and equipment, net
Electric plant	$	4,991,826		$	4,714,398
Construction work in progress	353,482			388,323
Total property, plant and equipment	5,345,308			5,102,721
Less accumulated depreciation	(1,824,578		)	(1,818,691		)
	$	3,520,730		$	3,284,030