Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Discontinued operations - current assets	$ 14,001	$ 12,743	$ 14,001	$ 12,743		$ 13,269
Discontinued operations - total assets		12,700		12,700
Discontinued operations current liabilities	13,279	12,922	13,279	12,922		12,959
Discontinued Operation, Income Statement Disclosures [Abstract]
Loss from discontinued operations, net of tax	(956)	(659)	(1,173)	(1,133)
Gill Ranch [Member] | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Accounts receivable	519	497	519	497		390
Inventories	756	646	756	646		685
Other current assets	183	413	183	413		333
Property, plant, and equipment	12,184	10,948	12,184	10,948		11,621
Less: Accumulated depreciation	6	6	6	6		7
Operating lease right of use asset	118	0	118	0		0
Other non-current assets	247	245	247	245		247
Discontinued operations - total assets	14,001	12,743	14,001	12,743		13,269
Accounts payable	1,230	572	1,230	572		873
Other current liabilities	296	436	296	436		307
Operating lease liabilities	113	0	113	0		0
Other non-current liabilities	11,640	11,914	11,640	11,914		11,779
Total discontinued operations liabilities	13,279	12,922	13,279	12,922		$ 12,959
Gill Ranch [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues	1,748	1,006	3,469	2,083
Operations and maintenance	2,651	1,554	4,264	2,590
General taxes	60	346	119	680
Depreciation and amortization	106	108	212	218
Other expenses and interest	229		466	134
Other interest		(107)
Total expenses	3,046	1,901	5,061	3,622
Loss from discontinued operations before income tax	(1,298)	(895)	(1,592)	(1,539)
Income tax benefit	(342)	(236)	(419)	(406)
Loss from discontinued operations, net of tax	$ (956)	$ (659)	$ (1,173)	$ (1,133)
Loss from discontinued operations per share of common stock
Basic (in dollars per share)	$ (0.03)	$ (0.02)	$ (0.04)	$ (0.04)
Diluted (in dollars per share)	$ (0.03)	$ (0.02)	$ (0.04)	$ (0.04)
Transferred Subsidiaries - NW Natural Discontinued Operations [Member] | Discontinued Operations, Disposed of by Means Other than Sale [Member]
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Cash		$ 433		$ 433
Accounts receivable		498		498
Receivables from affiliates		3,814		3,814
Inventories		646		646
Other current assets		482		482
Property, plant, and equipment		11,323		11,323
Less: Accumulated depreciation		213		213
Other investments		13,673		13,673
Other non-current assets		254		254
Discontinued operations - current assets		5,873		5,873
Discontinued operations - non-current assets		25,037		25,037
Discontinued operations - total assets		30,910		30,910
Accounts payable		971		971
Taxes accrued		30		30
Payables to affiliates		265		265
Other current liabilities		1,436		1,436
Deferred tax liabilities		(15,022)		(15,022)
Other non-current liabilities		12,004		12,004
Discontinued operations current liabilities		2,702		2,702
Discontinued operations non-current liabilities		(3,018)		(3,018)
Total discontinued operations liabilities		316		316
Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues		1,065		2,198
Operations and maintenance		1,684		2,743
General taxes		356		703
Depreciation and amortization		165		282
Other expenses and interest				110
Other interest		(150)
Total expenses		2,055		3,838
Loss from discontinued operations before income tax		(990)		(1,640)
Income tax benefit		(263)		(436)
Loss from discontinued operations, net of tax		$ (727)		$ (1,204)
Gill Ranch [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent ownership	75.00%		75.00%
Pacific Gas and Electric Company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent ownership	25.00%		25.00%
Scenario, Forecast [Member] | Minimum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses					$ 25,000
Scenario, Forecast [Member] | Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses					$ 26,500