Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock Including APIC [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Northwest Natural Gas Company [Member]	Northwest Natural Gas Company [Member] Northwest Natural Gas Company Consolidated [Member]	Northwest Natural Gas Company [Member] Common Stock Including APIC [Member]	Northwest Natural Gas Company [Member] Retained Earnings [Member]	Northwest Natural Gas Company [Member] Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2018	$ 762,634	$ 457,640	$ 312,182	$ (7,188)		$ 715,668	$ 226,452	$ 496,404	$ (7,188)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	59,556	0	61,735	(2,179)	$ 66,795	66,795	0	68,974	(2,179)
Dividends on common stock	(56,833)	0	(56,833)	0		(53,372)	0	(53,372)	0
Shares issued pursuant to equity based plans	2,601	2,601	0	0
Transfer from Investments						0	0	(1,366)	1,366
Capital contributions					93,155	93,105	93,105	0	0
Issuance of common stock, net of issuance costs	92,956	92,956	0	0
Shares issued pursuant to equity based plans	5,085	(5,085)	0	0
Reclassification of tax effects from the TCJA	0	0	1,366	(1,366)
Ending Balance at Dec. 31, 2019	$ 865,999	558,282	318,450	(10,733)		822,196	319,557	513,372	(10,733)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common stock (in dollars per share)	$ 1.90
Comprehensive income (loss)	$ 74,612	0	76,781	(2,169)	68,394	68,394	0	70,563	(2,169)
Dividends on common stock	(58,708)	0	(58,708)	0		(55,355)	0	(55,355)	0
Stock-based compensation	4,361	4,361	0	0
Stockholders' Equity, Other						51	51	0	0
Shares issued pursuant to equity based plans	2,469	2,469	0	0
Capital contributions					0
Ending Balance at Dec. 31, 2020	$ 888,733	565,112	336,523	(12,902)		835,184	319,506	528,580	(12,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common stock (in dollars per share)	$ 1.91
Comprehensive income (loss)	$ 80,164	0	78,666	1,498	82,670	82,670	0	81,172	1,498
Dividends on common stock	(59,410)	0	(59,410)	0		(56,056)	0	(56,056)	0
Stock-based compensation	3,615	3,615	0	0
Shares issued pursuant to equity based plans	4,543	4,543	0	0
Capital contributions					$ 116,009	116,009	116,009	0	0
Issuance of common stock, net of issuance costs	17,501	17,501	0	0
Ending Balance at Dec. 31, 2021	$ 935,146	$ 590,771	$ 355,779	$ (11,404)		$ 977,807	$ 435,515	$ 553,696	$ (11,404)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common stock (in dollars per share)	$ 1.92