v3.24.2.u1
Segment Information - Schedule of Summarized Financial Information by Segment - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Dec. 31, 2023
Segment Reporting Information [Line Items]          
Operating revenues $ 211,714 $ 237,859 $ 645,184 $ 700,282  
Depreciation 33,762 31,293 66,860 62,758  
Income from operations 15,706 13,843 125,533 127,351  
Total assets 4,822,366 4,536,705 4,822,366 4,536,705 $ 4,867,092
Natural Gas Distribution [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 194,862 223,714 612,726 671,484  
Depreciation 31,418 29,623 62,248 59,481  
Income from operations 11,788 10,390 119,761 119,549  
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent (2,987) (271) 62,728 71,680  
Capital expenditures - Segment, Expenditure, Addition to Long-Lived Assets 107,473 65,215 178,967 128,857  
Total assets 4,367,838 4,176,376 4,367,838 4,176,376 4,458,117
Other Northwest Natural [Member] | Corporate, Non-Segment [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 5,326 4,634 10,237 11,377  
Depreciation 240 257 517 543  
Income from operations 3,598 2,912 6,256 7,881  
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent 2,563 2,055 4,406 5,644  
Capital expenditures - Segment, Expenditure, Addition to Long-Lived Assets (495) 485 48 441  
Total assets 50,875 53,538 50,875 53,538 53,260
Northwest Natural Gas Company [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 200,188 228,348 622,963 682,861  
Depreciation 31,658 29,880 62,765 60,024  
Income from operations 15,386 13,302 126,017 127,430  
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent (424) 1,784 67,134 77,324  
Capital expenditures - Segment, Expenditure, Addition to Long-Lived Assets 106,978 65,700 179,015 129,298  
Total assets 4,418,713 4,229,914 4,418,713 4,229,914 4,511,377
Other Northwest Holdings [Member] | Corporate, Non-Segment [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 11,526 9,511 22,221 17,421  
Depreciation 2,104 1,413 4,095 2,734  
Income from operations 320 541 (484) (79)  
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent (2,363) (540) (6,098) (4,409)  
Capital expenditures - Segment, Expenditure, Addition to Long-Lived Assets 9,734 7,898 19,914 15,565  
Total assets 403,653 306,791 403,653 306,791 355,715
Northwest Natural Gas Company [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 200,188 228,348 622,963 682,861  
Depreciation 31,658 29,880 62,765 60,024  
Income from operations 15,386 13,302 126,017 127,430  
Total assets 4,418,713 4,229,914 4,418,713 4,229,914 4,511,377
Northwest Natural Gas Company [Member] | Natural Gas Distribution [Member] | Operating Segments [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 194,861 223,713 612,725 671,483  
Northwest Natural Gas Company [Member] | Other Northwest Natural [Member] | Corporate, Non-Segment [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 5,327 4,635 10,238 11,378  
Northwest Natural Gas Company [Member] | Northwest Natural Gas Company [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 200,188 228,348 622,963 682,861  
Parent Company [Member]          
Segment Reporting Information [Line Items]          
Operating revenues 211,714 237,859 645,184 700,282  
Depreciation 33,762 31,293 66,860 62,758  
Income from operations 15,706 13,843 125,533 127,351  
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent (2,787) 1,244 61,036 72,915  
Capital expenditures - Segment, Expenditure, Addition to Long-Lived Assets 116,712 73,598 198,929 144,863  
Total assets $ 4,822,366 $ 4,536,705 $ 4,822,366 $ 4,536,705 $ 4,867,092