Valuation Allowances and Reserves

12 Months Ended

Dec. 31, 2016

Valuation and Qualifying Accounts [Abstract]

Schedule of Valuation and Qualifying Accounts [Text Block]

NORTHWEST NATURAL GAS COMPANY

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS AND RESERVES

COLUMN A	COLUMN B		COLUMN C				COLUMN D		COLUMN E
			Additions				Deductions
In thousands (year ended December 31)	Balance at beginning of period		Charged to costs and expenses		Charged to other accounts		Net write-offs		Balance at end of period
2016
Reserves deducted in balance sheet from assets to which they apply:
Allowance for uncollectible accounts	$	870	$	1,246	$	—	$	826	$	1,290
2015
Reserves deducted in balance sheet from assets to which they apply:
Allowance for uncollectible accounts	$	969	$	760	$	—	$	859	$	870
2014
Reserves deducted in balance sheet from assets to which they apply:
Allowance for uncollectible accounts	$	1,656	$	599	$	—	$	1,286	$	969