Quarterly Financial Information (tables)

12 Months Ended

Dec. 31, 2011

Schedule Of Quarterly Financial Information [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

NORTHWEST NATURAL GAS COMPANY
QUARTERLY FINANCIAL INFORMATION (UNAUDITED)
			Quarter ended
Thousands, except per share amounts			March 31		June 30		Sept. 30		Dec. 31		Total
2011
Operating revenues		$	323,088	$	161,197	$	93,313	$	271,198	$	848,796
Net operating revenues			134,508		67,232		47,783		119,910		369,433
Net income (loss)			40,773		2,193		(8,312)		29,244		63,898
Basic earnings (loss) per share			1.53		0.08		(0.31)		1.09		2.39(1)
Diluted earnings (loss) per share			1.53		0.08		(0.31)		1.09		2.39(1)
2010
Operating revenues		$	286,529	$	162,365	$	95,067	$	268,145	$	812,106
Net operating revenues			130,926		72,193		46,211		118,251		367,581
Net income (loss)			43,608		6,888		(7,420)		29,591		72,667
Basic earnings (loss) per share			1.64		0.26		(0.28)		1.11		2.73(1)
Diluted earnings (loss) per share			1.64		0.26		(0.28)		1.11		2.73(1)
(1)	Quarterly earnings (loss) per share are based upon the average number of common shares outstanding during each quarter. Because the average number of shares outstanding has changed in each quarter shown, the sum of quarterly earnings (loss) per share may not equal earnings per share for the year. Variations in earnings between quarterly periods are due primarily to the seasonal nature of our business.