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, 2020	$ 888,733	$ 565,112	$ 336,523	$ (12,902)		$ 835,184	$ 319,506	$ 528,580	$ (12,902)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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
Shares issued in connection with business combinations	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 from parent					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
Comprehensive income (loss)	$ 91,422	0	86,303	5,119	96,554	96,554	0	91,564	4,990
Dividends on common stock	(65,609)	0	(65,609)	0		(62,667)	0	(62,667)	0
Shares issued in connection with business combinations	0
Stock-based compensation	3,228	3,228	0	0
Shares issued pursuant to equity based plans	2,978	2,978	0	0
Capital contributions from parent					179,388	179,388	179,388	0	0
Issuance of common stock, net of issuance costs	208,276	208,276	0	0
Ending Balance at Dec. 31, 2022	$ 1,175,441	805,253	376,473	(6,285)		1,191,082	614,903	582,593	(6,414)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common stock (in dollars per share)	$ 1.93
Comprehensive income (loss)	$ 93,104	0	93,868	(764)	103,914	103,914	0	104,737	(823)
Dividends on common stock	(70,430)	0	(70,430)	0		(92,376)	0	(92,376)	0
Shares issued in connection with business combinations	12,884	12,884	0	0
Stock-based compensation	3,598	3,598	0	0
Shares issued pursuant to equity based plans	2,328	2,328	0	0
Capital contributions from parent					$ 30,000	30,000	30,000	0	0
Issuance of common stock, net of issuance costs	66,913	66,913	0	0
Ending Balance at Dec. 31, 2023	$ 1,283,838	$ 890,976	$ 399,911	$ (7,049)		$ 1,232,620	$ 644,903	$ 594,954	$ (7,237)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on common stock (in dollars per share)	$ 1.94