Balancing and Memorandum Accounts - Public Utilities General Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue accounts:
Beginning Balance	$ 11,645	$ 6,658	$ 10,043	$ (1,940)
Regulatory Asset Increase (Decrease)	1,570	1,629	3,171	3,386
Refunds (Collections) Adjustments	5	0	6	6,841
Ending Balance	13,220	8,287	13,220	8,287
Cost-recovery accounts:
Beginning Balance	16,492	8,390	15,420	7,223
Regulatory Asset Increase (Decrease)	1,703	938	2,856	2,121
Refunds (Collections) Adjustments	(98)	0	(179)	(16)
Ending Balance	18,097	9,328	18,097	9,328
Total
Beginning Balance	28,137	15,048	25,463	5,283
Regulatory Asset Increase (Decrease)	3,273	2,567	6,027	5,507
Refunds (Collections) Adjustments	(93)	0	(173)	6,825
Ending Balance	$ 31,317	17,615	$ 31,317	17,615
Authorized revenue, threshold percentage	2.00%		2.00%
Monterey WRAM
Revenue accounts:
Beginning Balance	$ 13,853	8,958	$ 12,077	7,015
Regulatory Asset Increase (Decrease)	1,424	1,591	3,200	3,561
Refunds (Collections) Adjustments	1	0	1	(27)
Ending Balance	15,278	10,549	15,278	10,549
Cost of capital memorandum account
Revenue accounts:
Beginning Balance	(1,561)	(1,558)	(1,561)	(1,553)
Regulatory Asset Increase (Decrease)	(1)	(2)	(1)	(7)
Refunds (Collections) Adjustments	0	0	0	0
Ending Balance	(1,562)	(1,560)	(1,562)	(1,560)
Tax memorandum account
Revenue accounts:
Beginning Balance	333	332	333	(6,643)
Regulatory Asset Increase (Decrease)	0	0	0	(3)
Refunds (Collections) Adjustments	0	0	0	6,978
Ending Balance	333	332	333	332
All others
Revenue accounts:
Beginning Balance	(980)	(1,074)	(806)	(759)
Regulatory Asset Increase (Decrease)	147	40	(28)	(165)
Refunds (Collections) Adjustments	4	0	5	(110)
Ending Balance	(829)	(1,034)	(829)	(1,034)
Cost-recovery accounts:
Beginning Balance	445	443	445	446
Regulatory Asset Increase (Decrease)	1	1	1	2
Refunds (Collections) Adjustments	0	0	0	(4)
Ending Balance	446	444	446	444
Water supply costs
Cost-recovery accounts:
Beginning Balance	8,910	5,061	8,123	4,328
Regulatory Asset Increase (Decrease)	984	838	1,771	1,605
Refunds (Collections) Adjustments	1	0	1	(34)
Ending Balance	9,895	5,899	9,895	5,899
Pension
Cost-recovery accounts:
Beginning Balance	3,844	2,886	3,478	2,449
Regulatory Asset Increase (Decrease)	366	99	732	514
Refunds (Collections) Adjustments	0	0	0	22
Ending Balance	4,210	2,985	4,210	2,985
PRVMA
Cost-recovery accounts:
Beginning Balance	1,027	0	1,108	0
Regulatory Asset Increase (Decrease)	0	0	0	0
Refunds (Collections) Adjustments	(99)	0	(180)	0
Ending Balance	928	0	928	0
CEMA
Cost-recovery accounts:
Beginning Balance	2,266	0	2,266	0
Regulatory Asset Increase (Decrease)	352	0	352	0
Refunds (Collections) Adjustments	0	0	0	0
Ending Balance	$ 2,618	$ 0	$ 2,618	$ 0