Long Term Water Assets (Volume of Water Assets) (Details)	Mar. 31, 2013 acre_foot	Dec. 31, 2012 acre_foot
Banked water and water for future delivery
Company water bank	8,818	8,700
Total Company and AVEK banked water	22,796	22,540
Transferable Water with AVEK	14,786	14,786
SWP contracts	100,796	100,540
Total purchased water - third parties	41,026	40,770
AVEK
Banked water and water for future delivery
AVEK water bank	11,616	11,478
AVEK water for future delivery	2,362	2,362
SWP Contracts
Banked water and water for future delivery
SWP contracts	3,444	3,444
WRMWSD
Banked water and water for future delivery
Long Term Water Assets, Contracts with Company	15,547	15,547
TCWD
Banked water and water for future delivery
Total Company and AVEK banked water	38,945	38,945
Long Term Water Assets, Contracts with Company	5,278	5,278