Segment and Nonregulated Business Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 subsidiaries		Mar. 31, 2013		Dec. 31, 2013
Segment Reporting Information [Line Items]
Number of Subsidiaries	4
Operating revenue	$ 54,596		$ 50,139
Operating expense	48,542		44,366
Operating income (loss)	6,054		5,773
Net income (loss)	906		1,317
Depreciation and amortization	9,485		8,816
Senior note, mortgage and other interest expense	4,870		5,022
Income tax expense (benefit) in net income	561		930
Assets	1,123,935		1,098,691		1,109,986
Water Utility Services [Member] | Regulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	51,626		47,798
Operating expense	46,463		41,625
Operating income (loss)	5,163		6,173
Net income (loss)	903		1,600
Depreciation and amortization	8,977		8,322
Senior note, mortgage and other interest expense	4,081		4,152
Income tax expense (benefit) in net income	552		922
Assets	1,027,073		1,004,441
Water Utility Services [Member] | Nonregulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	1,228		1,086
Operating expense	872		1,682
Operating income (loss)	356		(596)
Net income (loss)	151		(508)
Depreciation and amortization	90		88
Senior note, mortgage and other interest expense	0		0
Income tax expense (benefit) in net income	124		(144)
Assets	16,965		16,171
Real Estate Services [Member] | Nonregulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	1,742		1,255
Operating expense	1,022		810
Operating income (loss)	720		445
Net income (loss)	204		636
Depreciation and amortization	418		406
Senior note, mortgage and other interest expense	237		320
Income tax expense (benefit) in net income	153		460
Assets	70,710		69,492
All Other [Member] | Nonregulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	0	[1]	0	[1]
Operating expense	185	[1]	249	[1]
Operating income (loss)	(185)	[1]	(249)	[1]
Net income (loss)	(352)	[1]	(411)	[1]
Depreciation and amortization	0	[1]	0	[1]
Senior note, mortgage and other interest expense	552	[1]	550	[1]
Income tax expense (benefit) in net income	(268)	[1]	(308)	[1]
Assets	9,187	[1]	8,587	[1]
SJW Corp. [Member] | Regulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	51,626		47,798
Operating expense	46,463		41,625
Operating income (loss)	5,163		6,173
Net income (loss)	903		1,600
Depreciation and amortization	8,977		8,322
Senior note, mortgage and other interest expense	4,081		4,152
Income tax expense (benefit) in net income	552		922
Assets	1,027,073		1,004,441
SJW Corp. [Member] | Nonregulated [Member]
Segment Reporting Information [Line Items]
Operating revenue	2,970		2,341
Operating expense	2,079		2,741
Operating income (loss)	891		(400)
Net income (loss)	3		(283)
Depreciation and amortization	508		494
Senior note, mortgage and other interest expense	789		870
Income tax expense (benefit) in net income	9		8
Assets	$ 96,862		$ 94,250

[1] The “All Other” category includes the accounts of SJW Corp. on a stand-alone basis.