Discontinued Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Discontinued operations - current assets	$ 14,632	$ 1,512		$ 13,269
Discontinued operations - non-current assets	0	10,859		0
Discontinued operations - total assets		12,400
Discontinued operations current liabilities	13,282	1,209		12,959
Discontinued operations non-current liabilities	0	11,979		0
Discontinued Operation, Income Statement Disclosures [Abstract]
Loss from discontinued operations, net of tax	(217)	(474)
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	1,277	193		390
Inventories	627	736		685
Other current assets	337	583		333
Property, plant, and equipment	12,033	10,812		11,621
Less: Accumulated depreciation	7	4		7
Operating lease right of use asset	118	0		0
Other non-current assets	247	51		247
Discontinued operations - current assets	14,632	1,512		13,269
Discontinued operations - non-current assets	0	10,859		0
Discontinued operations - total assets	14,632	12,371		13,269
Accounts payable	1,102	462		873
Taxes accrued	59	334		0
Other current liabilities	300	413		307
Operating lease liabilities	111	0		0
Other non-current liabilities	11,710	11,979		11,779
Discontinued operations current liabilities	13,282	1,209		12,959
Discontinued operations non-current liabilities	0	11,979		0
Total discontinued operations liabilities	13,282	13,188		$ 12,959
Gill Ranch [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues	1,721	1,077
Operations and maintenance	1,613	1,036
General taxes	59	334
Depreciation and amortization	106	110
Other expenses and interest	237	241
Total expenses	2,015	1,721
Loss from discontinued operations before income tax	(294)	(644)
Income tax benefit	(77)	(170)
Loss from discontinued operations, net of tax	$ (217)	$ (474)
Loss from discontinued operations per share of common stock
Basic (in dollars per share)	$ (0.01)	$ (0.02)
Diluted (in dollars per share)	$ (0.01)	$ (0.02)
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		$ 311
Accounts receivable		193
Receivables from affiliates		3,852
Inventories		736
Other current assets		639
Property, plant, and equipment		11,186
Less: Accumulated depreciation		203
Other investments		13,691
Other non-current assets		64
Discontinued operations - current assets		5,731
Discontinued operations - non-current assets		24,738
Discontinued operations - total assets		30,469
Accounts payable		731
Taxes accrued		368
Payables to affiliates		660
Other current liabilities		401
Deferred tax liabilities		(16,397)
Other non-current liabilities		12,067
Discontinued operations current liabilities		2,160
Discontinued operations non-current liabilities		(4,330)
Total discontinued operations liabilities		2,170
Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues		1,133
Operations and maintenance		1,059
General taxes		347
Depreciation and amortization		117
Other expenses and interest		260
Total expenses		1,783
Loss from discontinued operations before income tax		(650)
Income tax benefit		(173)
Loss from discontinued operations, net of tax		$ (477)
Gill Ranch [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percent ownership	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%
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