Long-Term Water Assets - Intangible Water Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Costs	$ 36,800	$ 36,800
Accumulated Depreciation	(11,998)	(10,964)
Net cost of purchased water contracts	24,802	25,836
Total cost water held for future use	31,302	28,319
Net investments in water assets	56,104	54,155
Contract-based intangible assets | Dudley-Ridge water rights
Finite-Lived Intangible Assets [Line Items]
Costs	11,581	11,581
Accumulated Depreciation	(4,704)	(4,342)
Contract-based intangible assets | Nickel water rights
Finite-Lived Intangible Assets [Line Items]
Costs	18,740	18,740
Accumulated Depreciation	(4,444)	(3,962)
Contract-based intangible assets | Tulare Lake Basin water rights
Finite-Lived Intangible Assets [Line Items]
Costs	6,479	6,479
Accumulated Depreciation	$ (2,850)	$ (2,660)