Long-Term Water Assets - Intangible Water Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Costs	$ 36,800	$ 36,800
Accumulated Depreciation	(9,601)	(8,241)
Net cost of purchased water contracts	27,199	28,559
Total cost water held for future use	24,633	18,571
Net investment in water assets	51,832	47,130
Contract-based intangible assets | Dudley-Ridge water rights
Finite-Lived Intangible Assets [Line Items]
Costs	12,203	12,203
Accumulated Depreciation	(3,860)	(3,377)
Contract-based intangible assets | Nickel water rights
Finite-Lived Intangible Assets [Line Items]
Costs	18,740	18,740
Accumulated Depreciation	(3,320)	(2,678)
Contract-based intangible assets | Tulare Lake Basin water rights
Finite-Lived Intangible Assets [Line Items]
Costs	5,857	5,857
Accumulated Depreciation	$ (2,421)	$ (2,186)