Selected Balance Sheet Data

6 Months Ended

Jun. 30, 2017

Balance Sheet Related Disclosures [Abstract]

Selected Balance Sheet Data

Selected Balance Sheet Data

(Thousands of Dollars)	June 30, 2017			Dec. 31, 2016
Accounts receivable, net (a)
Accounts receivable	$	58,587		$	58,896
Less allowance for bad debts	(4,247		)	(4,865		)
	$	54,340		$	54,031

^(a)  Accounts receivable, net includes an immaterial amount due from affiliates as of June 30, 2017 and Dec. 31, 2016, respectively.

(Thousands of Dollars)	June 30, 2017		Dec. 31, 2016
Inventories
Materials and supplies	$	7,117	$	6,582
Fuel	4,615		4,743
Natural gas	3,908		6,984
	$	15,640	$	18,309

(Thousands of Dollars)	June 30, 2017			Dec. 31, 2016
Property, plant and equipment, net
Electric plant	$	2,534,258		$	2,499,401
Natural gas plant	307,217			294,986
Common and other property	170,486			156,316
Construction work in progress	145,458			118,822
Total property, plant and equipment	3,157,419			3,069,525
Less accumulated depreciation	(1,157,072		)	(1,121,888		)
	$	2,000,347		$	1,947,637