Long Term Water Assets - Volume of Water Assets (Details)	Dec. 31, 2012 acre_foot	Dec. 31, 2011 acre_foot
Banked water and water for future delivery
Company Water Bank	8,700	6,700
Banked water and water for future delivery	22,540	17,962
Transferable water	14,786	14,786
Water assets	40,770	36,192
AVEK [Member]
Banked water and water for future delivery
AVEK Water Bank	11,478	8,900
AVEK water for future delivery	2,362	2,362
SWP contracts [Member]
Banked water and water for future delivery
SWP Contracts	3,444	3,444