Long-Term Water Assets - Tangible Water Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Long Lived Assets Held-for-sale [Line Items]
Total water held for future use at cost	$ 28,135	$ 24,633
Banked water and water for future delivery
Long Lived Assets Held-for-sale [Line Items]
Total water held for future use at cost	25,208	24,597
Transferable water
Long Lived Assets Held-for-sale [Line Items]
Total water held for future use at cost	$ 2,927	$ 36