SJW (SJW) 10-Q 6 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2020	Oct. 28, 2020
Document and Entity Information [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Entity File Number	1-8966
Entity Registrant Name	SJW GROUP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0066628
Entity Address, Address Line One	110 West Taylor Street,
Entity Address, City or Town	San Jose,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95110
City Area Code	(408)
Local Phone Number	279-7800
Entity Listing, Description	Common Stock, par value $0.001 per share
Trading Symbol	SJW
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		28,556,228
Entity Central Index Key	0000766829
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Document Transition Report	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
REVENUE	$ 165,863	$ 113,997	$ 428,826	$ 294,644
Production Expenses:
Purchased water	35,130	35,583	76,953	75,626
Power	3,994	2,294	10,145	4,947
Groundwater extraction charges	20,471	13,182	54,082	29,145
Other production expenses	10,092	5,295	30,465	15,553
Total production expenses	69,687	56,354	171,645	125,271
Administrative and general	19,529	14,712	58,917	40,411
Maintenance	4,550	4,923	15,970	13,977
Property taxes and other non-income taxes	7,797	4,065	22,362	12,041
Depreciation and amortization	22,417	15,122	66,552	45,368
Merger related expenses	0	1,737	0	6,113
Total operating expense	123,980	96,913	335,446	243,181
OPERATING INCOME	41,883	17,084	93,380	51,463
OTHER (EXPENSE) INCOME:
Interest on long-term debt and other interest expense	(13,174)	(6,588)	(39,638)	(19,093)
Pension non-service cost	(218)	(921)	(270)	(2,749)
Interest income on money market fund	0	2,165	0	6,339
Gain on sale of real estate investments	1,050	0	1,050	745
Other, net	1,130	303	2,935	1,210
Income before income taxes	30,671	12,043	57,457	37,915
Provision for income taxes	4,578	2,565	9,226	8,802
NET INCOME BEFORE NONCONTROLLING INTEREST	26,093	9,478	48,231	29,113
Less net income attributable to the noncontrolling interest	0	0	0	224
SJW GROUP NET INCOME	26,093	9,478	48,231	28,889
Other comprehensive income (loss), net	76	0	(49)	0
SJW GROUP COMPREHENSIVE INCOME	$ 26,169	$ 9,478	$ 48,182	$ 28,889
SJW GROUP EARNINGS PER SHARE
Basic (usd per share)	$ 0.91	$ 0.33	$ 1.69	$ 1.02
Diluted (usd per share)	0.91	0.33	1.68	1.01
DIVIDENDS PER SHARE	$ 0.32	$ 0.30	$ 0.96	$ 0.90
WEIGHTED AVERAGE SHARES OUTSTANDING
Basic (shares)	28,533,907	28,451,811	28,510,489	28,438,521
Diluted (shares)	28,703,343	28,549,928	28,687,012	28,528,002

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Utility plant:
Land	$ 34,938	$ 34,395
Depreciable plant and equipment	3,117,413	2,988,454
Construction in progress	117,546	112,232
Intangible assets	35,274	33,424
Utility plant, gross	3,305,171	3,168,505
Less accumulated depreciation and amortization	1,023,677	962,019
Utility plant, net	2,281,494	2,206,486
Real estate investments	58,085	57,699
Less accumulated depreciation and amortization	14,493	13,597
Total	43,592	44,102
Cash and cash equivalents:
Cash	20,211	12,944
Restricted cash	0	5,000
Accounts receivable:
Customers, net of allowances for uncollectible accounts	51,374	36,305
Income tax	2,222	8,837
Other	2,828	2,833
Accrued unbilled utility revenue	57,418	40,102
Current regulatory assets, net	4,758	6,472
Other current assets	16,091	9,553
Current assets	154,902	122,046
OTHER ASSETS:
Net regulatory assets, less current portion	132,216	113,945
Investments	13,629	12,928
Goodwill	627,036	628,287
Other	6,845	4,676
Other assets	779,726	759,836
Assets	3,259,714	3,132,470
Stockholders’ equity:
Common stock, $0.001 par value; authorized 70,000,000 shares; issued and outstanding shares 28,552,177 on September 30, 2020 and 28,456,508 on December 31, 2019	29	28
Additional paid-in capital	509,031	506,639
Retained earnings	403,923	383,191
Accumulated other comprehensive income	78	126
Total stockholders’ equity	913,061	889,984
Long-term debt, less current portion	1,307,612	1,283,597
Capitalization, Long-term Debt and Equity	2,220,673	2,173,581
CURRENT LIABILITIES:
Line of credit	125,803	117,209
Current portion of long-term debt	71,943	22,272
Accrued groundwater extraction charges, purchased water and power	27,607	17,211
Accounts payable	33,759	34,886
Accrued interest	17,586	13,140
Accrued payroll	10,599	11,570
Other current liabilities	18,101	18,279
Current liabilities	305,398	234,567
DEFERRED INCOME TAXES	186,952	195,598
ADVANCES FOR CONSTRUCTION	123,043	112,339
CONTRIBUTIONS IN AID OF CONSTRUCTION	291,482	286,035
POSTRETIREMENT BENEFIT PLANS	107,129	108,044
OTHER NONCURRENT LIABILITIES	25,037	22,306
COMMITMENTS AND CONTINGENCIES	0	0
Capitalization and liabilities	$ 3,259,714	$ 3,132,470

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, shares authorized (shares)	70,000,000	36,000,000
Common stock, shares issued (shares)	28,552,177	28,456,508
Common stock, shares outstanding (shares)	28,552,177	28,456,508

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interest [Member]	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, AdjustmentRetained Earnings
Beginning balance at Dec. 31, 2018	$ 889,312	$ 28	$ 495,366	$ 393,918	$ 0	$ 0	$ 97	$ 97
Beginning balance (in shares) at Dec. 31, 2018		28,404,316
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	5,873			5,873		0
Share-based compensation	870		886	(16)
Issuance of restricted and deferred stock units	(132)		(132)
Issuance of restricted and deferred stock units (in shares)		14,312
Employee stock purchase plan	811		811
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(10)		(10)
Employee stock purchase plan (in shares)		15,932
Dividends paid	(8,528)			(8,528)
Ending balance at Mar. 31, 2019	888,293	$ 28	496,921	391,344	0	0
Ending balance (in shares) at Mar. 31, 2019		28,434,560
Beginning balance at Dec. 31, 2018	889,312	$ 28	495,366	393,918	0	0	$ 97	$ 97
Beginning balance (in shares) at Dec. 31, 2018		28,404,316
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,113
Ending balance at Sep. 30, 2019	896,664	$ 28	499,377	397,259	0	0
Ending balance (in shares) at Sep. 30, 2019		28,456,490
Beginning balance at Mar. 31, 2019	888,293	$ 28	496,921	391,344	0	0
Beginning balance (in shares) at Mar. 31, 2019		28,434,560
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,762			13,538		224
Distribution to noncontrolling interest	(224)					(224)
Share-based compensation	702		718	(16)
Issuance of restricted and deferred stock units	(6)		(6)
Issuance of restricted and deferred stock units (in shares)		7,579
Dividends paid	(8,532)			(8,532)
Ending balance at Jun. 30, 2019	893,995	$ 28	497,633	396,334	0	0
Ending balance (in shares) at Jun. 30, 2019		28,442,139
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,478			9,478
Share-based compensation	936		952	(16)
Employee stock purchase plan	792		792
Employee stock purchase plan (in shares)		14,351
Dividends paid	(8,537)			(8,537)
Ending balance at Sep. 30, 2019	896,664	$ 28	499,377	397,259	0	0
Ending balance (in shares) at Sep. 30, 2019		28,456,490
Beginning balance at Dec. 31, 2019	$ 889,984	$ 28	506,639	383,191	126	0
Beginning balance (in shares) at Dec. 31, 2019	28,456,508	28,456,508
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 2,417			2,417
Unrealized Gain (Loss) on Investments	(135)				(135)
Share-based compensation	208		251	(43)
Issuance of restricted and deferred stock units	(785)		(785)
Issuance of restricted and deferred stock units (in shares)		25,781
Employee stock purchase plan	970		970
Employee stock purchase plan (in shares)		15,552
Dividends paid	(9,118)			(9,118)
Ending balance at Mar. 31, 2020	883,541	$ 28	507,075	376,447	(9)	0
Ending balance (in shares) at Mar. 31, 2020		28,497,841
Beginning balance at Dec. 31, 2019	$ 889,984	$ 28	506,639	383,191	126	0
Beginning balance (in shares) at Dec. 31, 2019	28,456,508	28,456,508
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 48,231
Ending balance at Sep. 30, 2020	$ 913,061	$ 29	509,031	403,923	78	0
Ending balance (in shares) at Sep. 30, 2020	28,552,177	28,552,177
Beginning balance at Mar. 31, 2020	$ 883,541	$ 28	507,075	376,447	(9)	0
Beginning balance (in shares) at Mar. 31, 2020		28,497,841
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,721			19,721		0
Unrealized Gain (Loss) on Investments	10				10
Share-based compensation	966		1,009	(43)
Issuance of restricted and deferred stock units	15	$ 1	14
Issuance of restricted and deferred stock units (in shares)		18,864
Dividends paid	(9,122)			(9,122)
Ending balance at Jun. 30, 2020	895,131	$ 29	508,098	387,003	1	0
Ending balance (in shares) at Jun. 30, 2020		28,516,705
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	26,093			26,093
Unrealized Gain (Loss) on Investments	77				77
Share-based compensation	1,016		1,058	(42)
Issuance of restricted and deferred stock units	(985)	$ 0	(985)
Issuance of restricted and deferred stock units (in shares)		19,274
Employee stock purchase plan	860		860
Employee stock purchase plan (in shares)		16,198
Dividends paid	(9,131)			(9,131)
Ending balance at Sep. 30, 2020	$ 913,061	$ 29	$ 509,031	$ 403,923	$ 78	$ 0
Ending balance (in shares) at Sep. 30, 2020	28,552,177	28,552,177

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity Parenthetical - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Provision for income taxes	$ 4,578			$ 2,565
OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax	$ 0	$ 4	$ (50)	$ 0	$ 0
DIVIDENDS PER SHARE	$ 0.32	$ 0.32	$ 0.32	$ 0.30	$ 0.30	$ 0.30
Cumulative Effect, Period of Adoption, Adjustment
Provision for income taxes						$ 33

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
OPERATING ACTIVITIES:
Net income	$ 48,231	$ 29,113
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	68,683	47,363
Deferred income taxes	(6,358)	(7,214)
Stock-based compensation	2,318	2,556
Gain on sale of real estate investments	(1,050)	(745)
Loss on sale of utility property	0	20
Changes in operating assets and liabilities:
Accounts receivable and accrued unbilled utility revenue	(34,491)	(20,553)
Accounts payable and other current liabilities	(3,877)	4,166
Accrued groundwater extraction charges, purchased water and power	10,396	9,055
Tax receivable and payable, and other accrued taxes	6,459	4,471
Postretirement benefits	408	2,514
Regulatory assets and liabilities related to balancing and memorandum accounts	(14,086)	22,789
Up-front service concession payment	(5,000)	0
Other changes, net	(1,018)	(2,258)
NET CASH PROVIDED BY OPERATING ACTIVITIES	70,615	91,277
INVESTING ACTIVITIES:
Company-funded	(130,426)	(101,120)
Contributions in aid of construction	(9,584)	(10,040)
Additions to real estate investments	(391)	(137)
Payments to retire utility plant, net of salvage	(1,877)	(4,374)
Proceeds from sale of real estate investments	1,068	745
Proceeds from sale of utility property	0	150
NET CASH USED IN INVESTING ACTIVITIES	(141,210)	(114,776)
FINANCING ACTIVITIES:
Borrowings on line of credit	226,884	73,000
Repayments on line of credit	(218,290)	(111,000)
Long-term borrowings	85,000	80,000
Repayments of long-term borrowings	(9,589)	0
Debt issuance and broker fee costs	(646)	(1,157)
Dividends paid	(27,371)	(25,596)
Receipts of advances and contributions in aid of construction	19,059	13,373
Refunds of advances for construction	(2,121)	(2,295)
Other changes, net	(64)	1,154
NET CASH PROVIDED BY FINANCING ACTIVITIES	72,862	27,479
NET CHANGE IN CASH AND CASH EQUIVALENTS	2,267	3,980
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, BEGINNING OF PERIOD	17,944	420,722
CASH AND CASH EQUIVALENTS, END OF PERIOD	20,211	424,702
Cash paid during the period for:
Interest	40,409	19,821
Income taxes	7,024	16,286
Supplemental disclosure of non-cash activities:
Change in accrued payables for construction costs capitalized	1,997	505
Utility property installed by developers	$ 5,051	$ (109)

General

General	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
GENERAL	General In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments (consisting only of normal, recurring adjustments) necessary for a fair presentation of the results for the interim periods. The unaudited interim financial information has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). The Notes to Consolidated Financial Statements in SJW Group’s 2019 Annual Report on Form 10-K should be read with the accompanying unaudited condensed consolidated financial statements. Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” and subsequent amendments. Topic 326 requires measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 was effective for SJW Group in the first quarter of fiscal 2020. The adoption of ASU 2016-13 did not have a material impact on the condensed consolidated financial statements. New Accounting Pronouncements Not Yet Adopted In August 2018, the FASB issued Accounting Standards Update (“ASU”) 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20: “Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans,” which aims to improve the overall usefulness of disclosure to financial statement users and reduce unnecessary costs to companies when preparing defined benefit plan disclosures. This update is effective for SJW Group’s Form 10-K for the year ending December 31, 2020. Retrospective adoption is required and early adoption is permitted. Management is currently evaluating the effect that the new standard will have on its defined benefit plan disclosures. In December 2019, the FASB issued ASU 2019-12, “Simplifying the Accounting for Income Taxes”, which simplifies the accounting for income taxes, eliminates certain exceptions within Topic 740, “Income Taxes”, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. This update is effective for fiscal years beginning after December 15, 2021. Most amendments within the standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. Management is currently evaluating the impacts of the provisions of ASU 2019-12 on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting”. ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by the expected transition away from reference rates that are expected to be discontinued, such as LIBOR. ASU 2020-04 was effective upon issuance. Companies may elect to apply the guidance prospectively through December 31, 2022. Management is evaluating the effect that the new standard will have on its consolidated financial statements. Revenue Water sales are seasonal in nature and influenced by weather conditions. The timing of precipitation and climatic conditions can cause seasonal water consumption by customers to vary significantly. Due to the seasonal nature of the water business, the operating results for interim periods are not indicative of the operating results for a 12-month period. Revenue is generally higher in the warm, dry summer months when water usage and sales are greater, and lower in the winter months when cooler temperatures and increased precipitation curtail water usage and sales. The major streams of revenue for SJW Group are as follows: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Revenue from contracts with customers $ 167,045 130,777 $ 414,344 314,003 Alternative revenue programs, net 1,324 (11,912 ) 4,877 (14,218 ) Other balancing and memorandum accounts revenue, net (3,909 ) (6,221 ) 5,388 (9,229 ) Rental income 1,403 1,353 4,217 4,088 $ 165,863 113,997 $ 428,826 294,644 Earnings per Share Basic earnings per share is calculated using income available to common stockholders, divided by the weighted average number of shares outstanding during the period. Diluted earnings per share is calculated using income available to common stockholders divided by the weighted average number of shares of common stock including both shares outstanding and shares potentially issuable in connection with restricted common stock awards under SJW Group’s Long-Term Incentive Plan (as amended, the “Incentive Plan”), shares potentially issuable under the performance stock plans assumed through the business combination with Connecticut Water Service, Inc. (“CTWS”), and shares potentially issuable under the Employee Stock Purchase Plan (“ESPP”). For the three months ended September 30, 2020 and 2019 , 1,029 and 524 anti-dilutive restricted common stock units were excluded from the dilutive earnings per share calculation, respectively. For the nine months ended September 30, 2020 and 2019 , 20,220 and 10,158 anti-dilutive restricted common stock units were excluded from the dilutive earnings per share calculation, respectively. Utility Plant Depreciation A portion of depreciation expense is allocated to administrative and general expense. For the three months ended September 30, 2020 and 2019 , the amounts allocated to administrative and general expense were $658 and $663 , respectively. For the nine months ended September 30, 2020 , and 2019 , the amounts allocated to administrative and general expense were $2,128 and $1,995

Equity Plans

Equity Plans	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
EQUITY PLANS	Equity Plans SJW Group accounts for stock-based compensation based on the grant date fair value of awards issued to employees in accordance with FASB ASC Topic 718 - “Compensation - Stock Compensation,” which requires the measurement and recognition of compensation expense based on the estimated fair value of stock-based payment awards. The Incentive Plan allows SJW Group to provide employees, non-employee board members or the board of directors of any parent or subsidiary, consultants, and other independent advisors who provide services to the company or any parent or subsidiary the opportunity to acquire an equity interest in SJW Group. The types of awards included in the Incentive Plan are restricted stock awards, restricted stock units, performance shares, or other share-based awards. As of September 30, 2020 , 182,367 shares are issuable upon the exercise of outstanding restricted stock units and deferred restricted stock units and an additional 743,038 shares are available for award issuances under the Incentive Plan. In addition, shares are issued to employees under the company’s ESPP. In connection with the merger with CTWS on October 9, 2019, SJW Group assumed outstanding awards of restricted stock units and deferred share units under the following stock plans: CTWS 2014 Performance Stock Program, CTWS 2004 Performance Stock Program and CTWS 1994 Performance Stock Program (collectively, the “CTWS Plans”). As of September 30, 2020 , approximately 66,430 shares are issuable upon the exercise of outstanding restricted stock units and deferred restricted stock units under the CTWS Plans. Stock compensation costs charged to income are recognized on a straight-line basis over the requisite service period. A summary of compensation costs charged to income and proceeds from the exercise of any restricted stock and similar instruments that are recorded to additional paid-in capital and common stock, by award type, are presented below for the three and nine months ended September 30, 2020 , and 2019 . Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Adjustments to additional paid-in capital and common stock for: Compensation costs charged to income: ESPP $ 152 140 $ 323 283 Restricted stock and deferred restricted stock 906 812 1,995 2,273 Total compensation costs charged to income $ 1,058 952 $ 2,318 2,556 ESPP proceeds $ 860 792 $ 1,830 1,603 Stock, Restricted Stock and Deferred Restricted Stock For the three months ended September 30, 2020 , and 2019 , SJW Group granted under the Incentive Plan 761 and 0 , respectively, three year service-based restricted stock awards with a weighted-average grant date fair value of $58.63 and $0 , respectively, per unit. For the nine months ended September 30, 2020 , and 2019 , SJW Group granted under the Incentive Plan 43,474 and 26,565 , respectively, one year and three year service-based restricted stock awards with a weighted-average grant date fair value of $63.87 and $51.42 , respectively, per unit. Performance-based and market-based restricted stock awards granted for the three months ended September 30, 2020 , and 2019 were 58 and 0 target units, respectively, with a weighted-average grant date fair value of $62.95 and $0 respectively, per unit. Performance-based and market-based restricted stock awards granted for the nine months ended September 30, 2020 , and 2019 were 24,777 and 30,401 target units, respectively, with a weighted-average grant date fair value of $65.02 and $60.46 , respectively, per unit. Based upon actual attainment relative to the target performance metric, the number of shares issuable can range between 0% to 150% of the target number of shares for performance-based restricted stock awards, or between 0% and 200% of the target number of shares for market-based restricted stock awards. As of September 30, 2020 , the total unrecognized compensation costs related to restricted and deferred restricted stock plans amounted to $4,987 . This cost is expected to be recognized over a weighted-average period of 1.86 years. Employee Stock Purchase Plan The ESPP allows eligible employees to purchase shares of SJW Group’s common stock at 85% of the fair value of shares on the purchase date. Under the ESPP, employees can designate up to a maximum of 10% of their base compensation for the purchase of shares of common stock, subject to certain restrictions. A total of 400,000 shares of common stock have been reserved for issuance under the ESPP. SJW Group’s recorded expenses were $85 and $244 for the three and nine months ended September 30, 2020 , respectively, and $82 and $223 for the three and nine months ended September 30, 2019 , respectively, related to the ESPP. The total unrecognized compensation costs related to the semi-annual offering period that ends January 29, 2021 , for the ESPP is approximately $116 . This cost is expected to be recognized during the fourth quarter of 2020 and first quarter of 2021.

Real Estate Investments

Real Estate Investments	9 Months Ended
	Sep. 30, 2020
Real Estate Investments, Net [Abstract]
REAL ESTATE INVESTMENTS	Real Estate Investments The major components of real estate investments as of September 30, 2020 , and December 31, 2019 , are as follows: September 30, December 31, Land $ 14,168 14,168 Buildings and improvements 43,917 43,531 Subtotal 58,085 57,699 Less: accumulated depreciation and amortization 14,493 13,597 Total $ 43,592 44,102 Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the assets, ranging from 7 to 39 years . Substantially all of the real estate investments relate to assets that are currently subject to operating leases. On September 28, 2020, San Jose Water Company sold six nonutility properties located in Los Gatos, California for $1,075 . SJW Group recognized a pre-tax gain on the sale of real estate investments of $1,048 , after selling expenses of $22 . On April 6, 2017, 444 West Santa Clara Street, L.P. sold all of its interest in the commercial building and land the partnership owned and operated. In connection with this sale, the partnership was required to deposit $750 into an escrow account for estimated repairs to the creek next to the land the partnership sold. On April 22, 2019, all creek repairs were completed and a reimbursement of $745 was provided to the partnership. SJW Land Company holds a 70% limited partner interest in 444 West Santa Clara Street, L.P. SJW Land Company and the noncontrolling interest recognized a pre-tax gain on the creek reimbursement of $521 and $224 , respectively, on the transaction.

Defined Benefit Plan

Defined Benefit Plan	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
DEFINED BENEFIT PLAN	Defined Benefit Plan SJW Group maintains noncontributory defined benefit pension plans for its eligible employees. San Jose Water Company (“SJWC”) and CTWS employees hired before March 31, 2008, and January 1, 2009, respectively, are entitled to benefits under the pension plans based on the employee’s years of service and compensation. Certain employees hired before March 1, 2012, and covered by a plan merged into the CTWS plan in 2013 are also entitled to benefits based on the employee’s years of service and compensation. For SJWC employees hired on or after March 31, 2008, benefits are determined using a cash balance formula based upon compensation credits and interest credits for each employee. CTWS employees hired on or after January 1, 2009, are entitled to an additional 1.5% of eligible compensation to their company sponsored savings plan. SJW Group does not have multi-employer plans. In addition, senior management hired before March 31, 2008, for SJWC and January 1, 2009, for CTWS are eligible to receive additional retirement benefits under supplemental executive retirement plans and retirement contracts. SJWC’s senior management hired on or after March 31, 2008, are eligible to receive additional retirement benefits under SJWC’s Cash Balance Executive Supplemental Retirement Plan. The supplemental retirement plans and Cash Balance Executive Supplemental Retirement Plan are non-qualified plans in which only senior management and other designated members of management may participate. SJW Group also provides health care and life insurance benefits for retired employees under employer-sponsored postretirement benefits other than pension plans. The components of net periodic benefit costs for the defined benefit plans and other postretirement benefits for the three and nine months ended September 30, 2020 , and 2019 are as follows: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Service cost $ 2,390 1,479 $ 7,170 4,437 Interest cost 2,860 2,113 8,580 6,338 Expected return on assets (4,126 ) (2,310 ) (12,429 ) (6,929 ) Unrecognized actuarial loss 1,296 1,056 3,888 3,168 Amortization of prior service cost 39 61 115 184 $ 2,459 2,399 $ 7,324 7,198 The following tables summarize the fair values of plan assets by major categories as of September 30, 2020 , and December 31, 2019 : Fair Value Measurements at September 30, 2020 Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents $ 7,921 7,921 — — Equity securities (a) 159,687 155,850 3,837 — Fixed income (b) 101,653 34,806 66,847 — Total $ 269,261 198,577 70,684 — ______________________________________ (a) Actively managed portfolio of equity securities with the goal to exceed the benchmark performance (b) Actively managed portfolio of fixed income securities with the goal to exceed the benchmark performance Fair Value Measurements at December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents $ 11,801 11,801 — — Equity securities (a) 157,050 149,265 7,785 — Fixed income (b) 91,896 31,686 60,210 — Total $ 260,747 192,752 67,995 — ______________________________________ (a) Actively managed portfolio of equity securities with the goal to exceed the benchmark performance (b) Actively managed portfolio of fixed income securities with the goal to exceed the benchmark performance In 2020 , SJW Group expects to make required and discretionary cash contributions of up to $14,594 to the pension plans and Social Welfare Plan. For the three and nine months ended September 30, 2020 , SJW Group has made $9,360 contributions to such plans.

Segment and Non-Tariffed Busine

Segment and Non-Tariffed Business Reporting	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
SEGMENT AND NONTARIFFED BUSINESS REPORTING	Segment and Non-Tariffed Business Reporting SJW Group is a holding company with four subsidiaries: (i) SJWC, a water utility operation with both regulated and non-tariffed businesses, (ii) SJWTX, Inc. which is doing business as Canyon Lake Water Service Company (“CLWSC”), a regulated water utility located in Canyon Lake, Texas, and its consolidated non-tariffed variable interest entity, Acequia Water Supply Corporation, (iii) SJW Land Company and its consolidated variable interest entity, 444 West Santa Clara Street, L.P., which operated commercial building rentals, and (iv) as of October 9, 2019, SJWNE LLC a holding company for CTWS and its subsidiaries, The Connecticut Water Company (“Connecticut Water”), The Maine Water Company (“Maine Water”), The Heritage Village Water Company (“HVWC”), The Avon Water Company (“Avon Water”), New England Water Utility Services, Inc. (“NEWUS”) and Chester Realty, Inc. On September 30, 2020 , Avon Water and HVWC merged into Connecticut Water after receiving merger approval from the Connecticut Public Utilities Regulatory Authority (“PURA”). In accordance with FASB ASC Topic 280 - “Segment Reporting,” SJW Group’s reportable segments have been determined based on information used by the chief operating decision maker. SJW Group’s chief operating decision maker includes the Chairman, President and Chief Executive Officer, and his executive staff. The first segment is that of providing water utility and utility-related services to its customers through SJW Group’s subsidiaries, SJWC, Connecticut Water, CLWSC, Maine Water, and NEWUS together referred to as “Water Utility Services.” The second segment is property management and investment activity conducted by SJW Land Company and Chester Realty, Inc., referred to as “Real Estate Services.” The following tables set forth information relating to SJW Group’s reportable segments and distribution of regulated and non-tariffed business activities within the reportable segments. Certain allocated assets, such as goodwill, revenue and expenses have been included in the reportable segment amounts. Other business activity of SJW Group not included in the reportable segments is included in the “All Other” category. For Three Months Ended September 30, 2020 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 161,646 2,814 1,403 — 161,646 4,217 165,863 Operating expense 119,885 2,161 961 973 119,885 4,095 123,980 Operating income (loss) 41,761 653 442 (973 ) 41,761 122 41,883 Net income (loss) 25,053 827 310 (97 ) 25,053 1,040 26,093 Depreciation and amortization 21,782 116 296 223 21,782 635 22,417 Interest on long-term debt and other interest expense 8,112 — — 5,062 8,112 5,062 13,174 Provision for income taxes 9,450 179 105 (5,156 ) 9,450 (4,872 ) 4,578 Assets $ 3,131,778 8,589 45,980 73,367 3,131,778 127,936 3,259,714 For Three Months Ended September 30, 2019 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 110,218 2,426 1,353 — 110,218 3,779 113,997 Operating expense 89,924 1,636 935 4,418 89,924 6,989 96,913 Operating income (loss) 20,294 790 418 (4,418 ) 20,294 (3,210 ) 17,084 Net income (loss) 10,964 555 304 (2,345 ) 10,964 (1,486 ) 9,478 Depreciation and amortization 14,712 111 299 — 14,712 410 15,122 Interest on long-term debt and other interest expense 6,044 — — 544 6,044 544 6,588 Provision for income taxes 2,912 216 95 (658 ) 2,912 (347 ) 2,565 Assets $ 1,556,049 5,899 46,160 414,274 1,556,049 466,333 2,022,382 For Nine Months Ended September 30, 2020 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 416,085 8,524 4,217 — 416,085 12,741 428,826 Operating expense 323,087 5,281 2,642 4,436 323,087 12,359 335,446 Operating income (loss) 92,998 3,243 1,575 (4,436 ) 92,998 382 93,380 Net income (loss) 53,117 3,178 1,141 (9,205 ) 53,117 (4,886 ) 48,231 Depreciation and amortization 64,654 332 896 670 64,654 1,898 66,552 Interest on long-term debt and other interest expense 24,575 — — 15,063 24,575 15,063 39,638 Provision for income taxes 16,101 909 361 (8,145 ) 16,101 (6,875 ) 9,226 Assets $ 3,131,778 8,589 45,980 73,367 3,131,778 127,936 3,259,714 For Nine Months Ended September 30, 2019 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 285,138 5,418 4,088 — 285,138 9,506 294,644 Operating expense 226,073 3,833 2,834 10,441 226,073 17,108 243,181 Operating income (loss) 59,065 1,585 1,254 (10,441 ) 59,065 (7,602 ) 51,463 Net income (loss) 30,726 1,127 1,284 (4,248 ) 30,726 (1,837 ) 28,889 Depreciation and amortization 44,159 313 896 — 44,159 1,209 45,368 Interest on long-term debt and other interest expense 17,434 — — 1,659 17,434 1,659 19,093 Provision for income taxes 9,142 438 445 (1,223 ) 9,142 (340 ) 8,802 Assets $ 1,556,049 5,899 46,160 414,274 1,556,049 466,333 2,022,382 * The “All Other” category for the nine months ended September 30, 2020 , includes the accounts of SJW Group, SJWNE LLC and CTWS on a stand-alone basis. For the three months ended September 30, 2019 , the “All Other” category includes the accounts of SJW Group and Hydro Sub, Inc. on a stand-alone basis. For the three months ended September 30, 2019 , Hydro Sub, Inc. had no recorded revenue or expenses and as of September 30, 2019 held no assets and incurred no liabilities. Hydro Sub. Inc. was a subsidiary created solely to facilitate the merger with CTWS and was dissolved following the completion of merger in October 2019.

Long-Term Liabilities and Bank

Long-Term Liabilities and Bank Borrowings (Notes)	9 Months Ended
	Sep. 30, 2020
Long-Term Liabilities and Bank Borrowings [Abstract]
LONG-TERM LIABILITIES AND BANK BORROWINGS	Long-Term Liabilities and Bank Borrowings SJW Group’s contractual obligations and commitments include senior notes, bank term loans, revenue bonds, state revolving fund loans, mortgages, and other obligations. Water Utility Services have received advance deposit payments from its customers on certain construction projects and the refunds of the advance deposit payments constitute an obligation of the respective subsidiaries. Lines of Credit On April 24, 2020, SJW Group and SJW Land Company entered into a Termination and Payoff agreement with JPMorgan Chase Bank, N.A. as the lender (the “Lender”) to terminate the SJW Group and SJW Land Company $15,000 credit agreement. On May 11, 2020, the SJWC entered into a Second Amendment (the “Second Amendment”) to SJWC’s existing $125,000 credit agreement, dated as of June 1, 2016, with the Lender, as amended by the First Amendment, dated January 12, 2018, (collectively, the “Existing SJWC Credit Agreement”), with the Lender. The Second Amendment amends the existing SJWC Credit Agreement to, among other things, increase the total commitment by $15,000 , from $125,000 to $140,000 . Also on May 11, 2020, SJWC entered into a $50,000 credit agreement (the “New SJWC Credit Agreement”) with the Lender. Proceeds of borrowings under the New SJWC Credit Agreement may be used to refinance existing debt, for working capital, and for general corporate purposes. The New SJWC Credit Agreement has a maturity date of November 11, 2020. Borrowings under the New SJWC Credit Agreement bear interest at either the Alternate Base Rate (“ABR”) or the LIBOR (as defined in the New SJWC Credit Agreement) rate. ABR borrowings (which are borrowings bearing interest at a rate determined by reference to the ABR) will bear interest at a rate per annum equal to (i) the greatest of (a) the prime rate in effect on such day, (b) the federal funds effective rate on such day plus 0.5% , and (c) the adjusted LIBOR rate for a one-month interest period on such day plus 1% plus (ii) the Applicable Rate (as defined in the New SJWC Credit Agreement), which is determined based on a pricing grid that is dependent upon the credit rating of SJWC as determined by either S&P or Moody’s. Eurodollar borrowings under the New SJWC Credit Agreement will bear interest at a rate per annum equal to (i) the adjusted LIBOR rate for the interest period in effect plus (ii) the Applicable Rate. The New SJWC Credit Agreement contains customary representations, warranties and events of default, as well as certain restrictive covenants customary for facilities of this type, including restrictions on indebtedness, liens, acquisitions and investments, restricted payments, asset sales, and fundamental changes. The New SJWC Credit Agreement also includes certain financial covenants that require SJWC to maintain a maximum funded debt to capitalization ratio and a minimum interest coverage ratio and to limit SJWC’s maximum consolidated cash balance. On May 29, 2020, CTWS entered into a Second Amendment to the CTWS’s existing $15,000 credit agreement, dated as of August 6, 2014, with CoBank, ACB (“CoBank), as amended by the First Amendment, dated October 28, 2015. The Second Amendment amends the prior agreement to, among other things, increase the total commitment by $25,000 , from $15,000 to $40,000 and extend the maturity date to May 15, 2025. Long-Term Debt On March 12, 2020, Connecticut Water entered into a note purchase agreement with the purchasers listed in the agreement, pursuant to which Connecticut Water sold on the same date an aggregate principal amount of $35,000 of its 3.51% Senior Notes, due March 12, 2050. The notes are unsecured obligations of Connecticut Water. Interest is payable semi-annually in arrears on March 12th and September 12th of each year. The note purchase agreement contains customary representations and warranties. Under the note purchase agreement, Connecticut Water is required to comply with certain customary affirmative and negative covenants for as long as the notes are outstanding. The notes are also subject to customary events of default, the occurrence of which may result in all of the notes then outstanding becoming immediately due and payable. The notes have terms and conditions that restrict Connecticut Water from issuing additional debt or paying a dividend to CTWS if such debt or distribution would trigger an event of default. The note purchase agreement also requires Connecticut Water to maintain a debt to capitalization ratio of not more than 60% and an interest coverage ratio at each fiscal quarter end of no less than three-to-one. As of September 30, 2020 , Connecticut Water was in compliance with all financial ratio and operational covenants under this note purchase agreement. On December 19, 2019, Maine Water issued $5,000 of Series S First Mortgage Bonds to the Maine Municipal Bond Bank through the State Safe Drinking Water Revolving Loan Fund. The Series S bonds mature on October 1, 2039, and carry 1% interest. The Series S First Mortgage Bond covenants are the same as all other First Mortgage Bonds. The proceeds were held as restricted cash by a trustee to be used for pre-approved projects primarily related to preliminary engineering and design work of a new water treatment plant in Maine Water’s Biddeford and Saco division. Proceeds were held by a trustee for the bond until conditions were met. On February 3, 2020, and March 11, 2020, the trustee released proceeds of $4,114 and $886 , respectively, from the bond. The associated bond indentures and loan agreements contain customary affirmative and negative covenants, including a prohibition on the issuance of indebtedness secured by assets or revenue of Maine Water where the lien is senior to the lien of the bond trustee under the above bonds except as permitted by the bond indentures and related loan and security agreements, a requirement to maintain a debt to capitalization ratio of not more than 65% , required compliance with various financial and operational covenants, and a provision for maturity acceleration upon the occurrence of stated events of default. On August 11, 2020, SJW Group entered into a note purchase agreement with the purchasers listed in the agreement, pursuant to which SJW Group sold an aggregate principal amount of $50,000 of its 2.47%

Income Taxes (Notes)

Income Taxes (Notes)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes For the three and nine months ended September 30, 2020 , income tax expense was $4,578 and $9,226 , respectively. Income tax expense for the three and nine months ended September 30, 2019 , was $2,565 and $8,802 , respectively. The effective consolidated income tax rates were 15% and 21% for the three months ended September 30, 2020 and 2019 , respectively, and 16% and 23% for the nine months ended September 30, 2020 , and 2019 , respectively. The lower effective rates for the three and nine months ended September 30, 2020 , were primarily due to flow-through tax benefits. SJW Group had unrecognized tax benefits of approximately $6,594 and $3,834 as of September 30, 2020 and December 31, 2019 , respectively. SJW Group does not expect its unrecognized tax benefits to change significantly within the next 12 months. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act was signed into law. The CARES Act includes, among other items, measures concerning income taxes. SJW Group has considered the income tax implications of the CARES Act in its estimated tax provision and does not believe it will materially impact the company’s year-end tax rate.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENT	Fair Value Measurement The following instruments are not measured at fair value on SJW Group’s condensed consolidated balance sheets as of September 30, 2020 , but require disclosure of their fair values: cash and cash equivalents, accounts receivable and accounts payable. The estimated fair value of such instruments as of September 30, 2020 , approximates their carrying value as reported on the condensed consolidated balance sheets. The fair value of such financial instruments are determined using the income approach based on the present value of estimated future cash flows. There have been no changes in valuation techniques during the three and nine months ended September 30, 2020 . The fair value of these instruments would be categorized as Level 2 in the fair value hierarchy, with the exception of cash and cash equivalents, which would be categorized as Level 1. The fair value of pension plan assets is discussed in Note 4. SJW Group has investments in company owned life insurance which are valued at cash surrender value of the policies as reported by the insurer. These contracts are based principally on a referenced pool of investment funds that actively redeem shares, are observable and measurable, and are presented in “Investments” on SJW Group’s consolidated balance sheets. As of September 30, 2020 , the value of the company owned life insurance was $7,497 of which $3,913 was related to assets to fund CTWS’s supplemental retirement plan agreements. As of December 31, 2019 , the value of the company owned life insurance was $7,086 of which $3,829 was related to assets to fund CTWS’s supplemental retirement plan agreements. In addition to life insurance contracts, CTWS’s supplemental retirement plan agreements are also funded with a Rabbi Trust. The following tables summarize the fair values of the Rabbi Trust investment assets to fund CTWS’s additional retirement benefits under the supplemental executive retirement plans and retirement contracts by major categories as of September 30, 2020 , and December 31, 2019 : Fair Value Measurements at September 30, 2020 Asset Category Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market funds $ 38 38 — — Mutual funds 2,021 2,021 — — Fixed income 815 815 — — Total $ 2,874 2,874 — — Fair Value Measurements at December 31, 2019 Asset Category Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Money market funds $ 20 20 — — Mutual funds 834 834 — — Fixed income 2,329 2,329 — — Total $ 3,183 3,183 — — The fair value of SJW Group’s long-term debt was approximately $1,575,067 and $1,396,205 as of September 30, 2020 , and December 31, 2019 , respectively, and was determined using a discounted cash flow analysis, based on the current rates for similar financial instruments of the same duration and creditworthiness of the company. The book value of the long-term debt was $1,379,555 and $1,305,869 as of September 30, 2020 , and December 31, 2019 , respectively. The fair value of long-term debt would be categorized as Level 2 in the fair value hierarchy.

Regulatory Rate Filings

Regulatory Rate Filings	9 Months Ended
	Sep. 30, 2020
Regulated Operations [Abstract]
REGULATORY RATE FILINGS	Regulatory Rate Filings California Regulatory Affairs On July 20, 2018, the California Public Utilities Commission (“CPUC”) issued an Order Instituting Investigation (“OII”) No. 18-07-007 concerning SJW Group’s then proposed merger with CTWS. A Scoping Memorandum was issued on September 7, 2018, which identified the issues to be considered in the proceeding as to whether the proposed merger is subject to CPUC approval and to evaluate the merger’s likely impacts within California. On September 14, 2018, SJW Group and SJWC submitted joint comments in response to the issues identified in accordance with the Scoping Memorandum’s adopted schedule, and reply comments were submitted on October 19, 2018. A Public Participation Hearing was held on January 31, 2019. On March 4, 2019, the CPUC suspended this proceeding due to SJW Group’s announcement of its intention to file a new merger approval application with the PURA. On April 3, 2019, SJW Group and CTWS jointly filed a new merger application with PURA. After securing the required approvals from both PURA and the Maine Public Utilities Commission (“MPUC”), SJW Group announced the close of the merger on October 9, 2019, and notified the CPUC accordingly. On August 31, 2020, the CPUC issued Decision 20-08-036 dismissing the OII and closing the proceeding. The OII is officially concluded as no application for rehearing was filed within 30 days of decision issuance. On September 14, 2018, the CPUC issued OII No. 18-09-003 to which SJWC was named as Respondent. The OII was to determine whether the company unlawfully overcharged customers over a 30-year period by failing to pro-rate service charges when increases occurred during a billing period, and whether the company double-billed service charges during one billing period when allegedly switching from billing such charges in advance to billing in arrears. The OII resulted from a report by the CPUC’s Consumer Protection and Enforcement Division (“CPED”), dated August 16, 2018, recommending an investigation into SJWC’s billing practice. CPED calculated a refund obligation of approximately $2,061 for the years 2014 to 2016 that had been the subject of SJWC’s Advice Letter No. 510. CPED calculated a further refund obligation of approximately $1,990 for the years 1987 to 2013. CPED also asserted that the company double-billed its customers during a billing period when it allegedly converted from billing in advance to billing in arrears, assumed that such double-billing occurred in January 2011, and calculated a refund obligation of approximately $4,935 . The OII notes these estimates and identifies the proper refund amount as an issue in the proceeding. The OII also identifies the CPUC’s authority to consider imposing penalties on SJWC in amounts ranging from $0.5 to $50 per offense, per day. On July 24, 2019, SJWC and CPED jointly filed a motion for CPUC approval of a Settlement Agreement (“Agreement”) over SJWC’s past customer billing practices. The Agreement requires the company to pay approximately $2,100 in customer credits, consisting of $1,757 for refunds during the period from 1987 to 2011 and an additional $350 in customer credits to low-income water customers, and invest $5,000 in utility plant that is not allowed an investment return or rate recovery. The Agreement was subject to final approval by the CPUC. A CPUC Presiding Officer’s Decision approved the Agreement in December 2019, but an appeal was filed in January 2020 by a group of SJWC customers. A final CPUC decision approving the Agreement and dismissing the appeal was approved on February 27, 2020, and concluded this proceeding. Advice Letter No. 545 was filed on March 13, 2020, requesting authorization to provide refunds to customers. For a typical residential customer with a 3/4-inch meter, the one-time refund was $5.52 dollars . This advice letter was approved effective April 12, 2020, and SJWC completed issuing refunds in mid-June 2020. On June 19, 2019, the CPUC issued its final decision resolving the remaining issues in SJWC’s general rate case for 2019. Decision 19-06-010 denied the establishment of a WRAM/SRM and authorized the recovery of the Hydro Generation Research, Development and Demonstration Memorandum Account balance as of September 30, 2016. SJWC filed Advice Letter No. 534 on August 1, 2019, to recover the $1,243 Hydro Generation Memorandum Account balance as of September 30, 2017, via a surcharge over a three-year period. The CPUC rejected the advice letter on October 10, 2019, citing an error in the name of the memorandum account and recommended a correction and a new filing for recovery. SJWC filed to correct the record and received the CPUC’s decision on April 10, 2020. Advice Letter 548 was filed on April 24, 2020, requesting recovery of $1,224 via a 36-month surcharge. The adjustment in the memorandum account balance reflected project costs incurred after September 30, 2016, which are not allowable per Decision 19-06-010. Per Resolution W-5228 approved on August 27, 2020 by the CPUC, further adjustments were made to the memorandum account balance resulting in an approved recovery of $1,219 which was recognized in the company’s regulatory assets as of September 30, 2020 . The recovery was approved in Advice Letter 548A effective August 31, 2020. SJWC filed Advice Letter No. 537 with the CPUC requesting authorization to refund the balance in its 2018 Tax Accounting Memorandum Account as required by the general rate case decision on October 18, 2019. On December 3, 2019, Advice Letter 537-A was filed to refund the balance via a one-time surcredit. For a typical residential customer with a 3/4-inch meter, the one-time refund will be $20.84 dollars per customer. This advice letter was approved effective January 21, 2020, and refunds to customers began and completed in January 2020. SJWC filed Advice Letter No. 541 on November 20, 2019, with the CPUC requesting authorization to increase its revenue requirement by $8,600 or 2.28% in 2020 for the first escalation year authorized in our 2018 General Rate Case Decision 18-011-025 which established rates for 2019, 2020, and 2021. This advice letter was approved on December 26, 2019, and new rates became effective January 1, 2020. On December 6, 2019, SJWC filed Application No. 19-12-002 with the CPUC requesting approval for cost recovery to deploy Advanced Metering Infrastructure throughout its service area. The application seeks revenue increases of $2,315 or 0.61% in 2021, $3,960 or 1.04% in 2022, $2,510 or 0.65% in 2023, and $341 or 0.09% in 2024 based on current rates in effect. A decision from the CPUC is anticipated in the fourth quarter of 2020. On January 22, 2020, SJWC, along with three other California water utilities, filed a joint request for a one-year deferment on the Cost of Capital filings which would otherwise be due on May 1, 2020. Postponing the filing one year would alleviate administrative processing costs on the utilities as well as the CPUC staff, and provide relief for both CPUC and utility resources already strained by numerous other proceedings. The request was conditioned on no changes to the current Water Cost of Capital Mechanism in place during the one-year deferment. On March 11, 2020, the CPUC approved the request. On March 16, 2020, the CPUC ordered its regulated water utilities to halt customer disconnection activities in connection with the COVID-19 pandemic. On April 16, 2020, the CPUC issued Executive Order N-42-20 suspending customer disconnection activities. The CPUC’s and Governor’s orders will remain in effect until further notice. On April 16, 2020, the CPUC issued Resolution M-4842 directing utilities to implement emergency customer protections to assist customers such as waiving reconnection deposits, offering payment arrangements, and suspending disconnections for nonpayment, to assist customers. This resolution is effective for up to one year, or April 16, 2021, with the option to extend. On March 19, 2020, SJWC filed Advice Letter 546 to extend customer protections listed in the company’s Disaster Relief Customer Protections and Outreach Plan as required by the CPUC in response to the COVID-19 pandemic. The filing also activated SJWC’s Catastrophic Event Memorandum Account (“CEMA”) to track costs related to SJWC’s response which includes labor and materials, anticipated increase in bad debt from the suspension of shutoffs for non-payment, waived deposits and reconnection fees, and divergence from actual versus authorized usage. The customer protections and CEMA were approved effective March 4, 2020. SJWC anticipates requesting recovery of the COVID-19 pandemic response costs in a future general rate case or other filings. SJWC filed Advice Letter No. 552 with the CPUC requesting authorization to establish a Polyfluoroalkyl Substances Memorandum Account (“PFAS MA”) on August 18, 2020. The advice letter was approved retroactive to March 1, 2019. SJWC will track in this account incremental expenses related to PFAS monitoring, sampling, and customer outreach activities for potential future recovery. Connecticut Regulatory Affairs As of September 30, 2020 , Water Infrastructure Conservation Adjustment (“WICA”) surcharges for Connecticut Water and Avon Water were 5.75% and 9.31% , respectively. HVWC did not have an approved WICA surcharge. On January 28, 2020, Connecticut Water filed a WICA application representing an additional 2.6% surcharge, for a cumulative WICA surcharge of 5.84% . Additionally, on February 7, 2020, Connecticut Water filed its annual WICA reconciliation which called for a 0.09% reduction of the WICA surcharge. On March 25, 2020, PURA approved a net cumulative 5.75% surcharge for Connecticut Water which became effective on customers’ bills on April 1, 2020. On October 28, 2020, Connecticut Water filed a WICA application representing an additional 1.11% surcharge or approximately $956 increase in revenues, for a cumulative WICA surcharge of 6.85% which is scheduled to become effective January 1, 2021. On March 3, 2020, Connecticut Water filed an application, Docket No. 20-03-04, with PURA to merge Avon Water and HVWC with and into Connecticut Water. The application was made to streamline borrowings, regulatory filings and internal administrative tasks associated with maintaining separate corporate entities and was approved by PURA on September 16, 2020. The merger became effective on September 30, 2020 . After the approval and prior to the completion of the merger, the outstanding debt balances held at Avon Water and HVWC were repaid in full. On March 12, 2020, PURA issued Docket No. 20-03-15 to establish a State of Emergency Utility Shut-off Moratorium for the COVID-19 pandemic. The moratorium ordered regulated utility companies to refrain from terminating utility service to residential customers, except for safety reasons until August 1, 2020, or until such other time as determined by the PURA. The moratorium was extended through October 1, 2020 at which time the company may resume standard collection practices until or unless there is further action by PURA. In the same docket, PURA further directed the public service companies to maintain a detailed record of costs incurred and revenues lost as a result of implementing its orders in the docket and may establish a regulatory asset to track incurred costs. Approval for recovery of additional costs incurred and/or revenues lost relating to the COVID-19 pandemic would be considered for recovery in the Connecticut Water’s next general rate case proceeding. Legislation was recently passed in Connecticut that made changes to the PURA statutes for utility regulation. The most notable changes that affect water companies were adjustments to extend the timelines for adjudication of various regulatory proceedings. In particular, the following proceeding timelines were increased: general rate case from 150 days with 30 day extension (180 days maximum) to 200 days, change in control from 120 days with 30 day extension (150 days maximum) to 200 days with an opportunity for a 30 day extension (230 days maximum), and financing from 30 days to 60 days. In addition, there is a new requirement that any future change in control or merger approvals would require the composition of the board of directors of the holding company to include a proportional percentage of Connecticut-based directors. The law also authorizes, but does not require, the PURA to consider adoption of a framework for performance-based regulation of private water companies. Texas Regulatory Affairs As required, CLWSC submitted on January 27, 2020, its Water Pass-Through Charge (“WPC”) true-up report for the Canyon Lake area systems 2019 purchased water costs. The WPC is the annual filing to change the component of CLWSC’s water rates for changes in purchased water costs since the last annual true-up report. The changes in the purchased water costs for the Deer Creek Ranch water system resulted in a decrease in the usage charge from $2.19 dollars to $2.02 dollars per thousand gallons, and an increase in the monthly base charge of $3.04 dollars per residential account. The Deer Creek Ranch rate changes became effective October 1, 2019. The 2019 WPC true-up report for the water systems located in the Canyon Lake area resulted in a reduction of the WPC usage rate from $1.05 dollars to $0.95 dollars per thousand gallons which became effective on February 1, 2020. The WPC filings for Deer Creek Ranch and the Canyon Lake area were approved by the Public Utilities Commission of Texas (“PUCT”) and a new tariff with the WPC rates was issued in May 2020. In connection with the disaster declaration in Texas, the PUCT issued Order No. 50664-106 to mitigate the impact of the COVID-19 pandemic on residential water utility customers. CLWSC responded to these orders by stopping disconnections for nonpayment of utility bills, and not charging fees for late payment. The PUCT allowed this order to expire on June 13, 2020. The PUCT also issued Accounting Orders under No. 50664-108, which instructs utilities to record the incremental costs and lost revenues from the COVID-19 pandemic in a regulatory tracking account for recovery in future rates. These amounts will be considered by the PUCT for recovery in each utility’s next rate application. Maine Regulatory Affairs On December 20, 2019, Maine Water filed for a general rate increase for their Skowhegan Division seeking approximately $221 , or 14.7% , in additional revenue with the MPUC. On June 17, 2020, the MPUC approved a general rate increase for Skowhegan Division customers allowing $198 in additional revenue. Per the MPUC decision, the increase will be implemented in two steps: an initial 9.80% rate increase effective June 15, 2020, and a 3.51% rate increase effective July 1, 2021. The combined rate increase is 13.31% . On January 20, 2020, Maine Water filed Water Infrastructure Surcharge (“WISC”) applications with the MPUC in four divisions requesting an increase between 1.76% and 3.00% , representing approximately $371 in additional revenues. The WISC applications were approved on February 26, 2020, and the surcharges became effective March 1, 2020. On March 16, 2020, MPUC issued an emergency moratorium on utility disconnection activities in connection to the COVID-19 pandemic. The moratorium directed public utility companies not to engage in any disconnection activities including disconnection notices for all classes of customers until further notice from MPUC. Maine Water is tracking COVID-19 related costs for potential future recovery in rates charged to customers. On September 17, 2020, the MPUC issued an order lifting the moratorium on utility disconnections in Maine effective November 1, 2020. The Order requires specific notifications by utilities to their customers prior to resuming disconnection activities and requires a waiver of late payment fess for customers who enter into payment arrangements on or before December 31, 2020. MWC is processing customer notices as required with the intention of resuming utility disconnections in November, 2020. On October 9, 2020, Maine Water filed a request for approval of a special rate contract between Maine Water and the Kennebec Water District (“KWD”). Maine Water has purchased water from KWD under a special rate contract approved by the MPUC since November 2000. The filing seeks to continue the existing relationship between the two water utilities and requests extension of the expiring 20 year agreement for an additional 20 years.

Balancing and Memorandum Accoun

Balancing and Memorandum Accounts	9 Months Ended
	Sep. 30, 2020
Regulated Operations [Abstract]
BALANCING AND MEMORANDUM ACCOUNTS	Balancing and Memorandum Accounts SJWC has established balancing accounts for the purpose of tracking the under-collection or over-collection associated with expense changes and the revenue authorized by the CPUC to offset those expense changes. SJWC also maintains memorandum accounts to track revenue impacts due to catastrophic events, certain unforeseen water quality expenses related to new federal and state water quality standards, energy efficiency, water conservation, water tariffs, and other approved activities or as directed by the CPUC. The Monterey Water Revenue Adjustment Mechanism (“WRAM”) tracks the difference between the revenue received for actual metered sales through the tiered volumetric rate and the revenue that would have been received with the same actual metered sales if a uniform rate would have been in effect. Balancing and memorandum accounts are recognized by SJWC when it is probable that future recovery of previously incurred costs or future refunds that are to be credited to customers will occur through the ratemaking process. In addition, in the case of special revenue programs such as the Water Conservation Memorandum Account (“WCMA”) and Water Revenue Adjustment (“WRA”), SJWC and CTWS follow the requirements of ASC Topic 980-605-25—“Alternative Revenue Programs” in determining revenue recognition, including the requirement that such revenues will be collected within 24 months of the year-end in which the revenue is recorded. A reserve is recorded for amounts SJW Group estimates will not be collected within the 24-month period. This reserve is based on an estimate of actual usage over the recovery period. In assessing the probability criteria for balancing and memorandum accounts between general rate cases, SJWC considers evidence that may exist prior to CPUC authorization that would satisfy ASC Topic 980-340-25—“Other Assets and Deferred Costs” recognition criteria. Such evidence may include regulatory rules and decisions, past practices, and other facts and circumstances that would indicate that recovery or refund is probable. When such evidence provides sufficient support, the balances are recorded in SJW Group’s condensed consolidated financial statements. CPUC approved Advice Letter No. 548A for the recovery of the Hydro Generation Research, Development and Demonstration Memorandum Account (“PRVMA”) on August 27, 2020. In 2016, the Company determined recovery at the time was not probable and recorded a reserve for the costs related to the project. Advice Letter No. 548A allowed recovery of $1,219 which was recognized as a regulatory asset for the three and nine months ended September 30, 2020 , and the reserve previously recognized was reversed. The amounts have been reflected in the PRVMA balances shown in the table below. On December 19, 2019, the CPUC denied the recovery of SJWC’s 2018 WCMA in Advice Letter No. 532 and no longer approved the tracking of WCMA balances. As a result of conflicting CPUC proposed decisions issued in October 2019 on recovery of the 2018 WCMA balance, SJWC determined that it no longer met the probability criteria for recognition under ASC Topic 980-605-25 and fully reserved the 2019 and 2018 WCMA balances as of September 30, 2019. Three months ended September 30, 2020 Three months ended September 30, 2019 Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Revenue accounts: Monterey WRAM $ 10,549 (1,124 ) 2,625 12,050 $ 8,986 328 (1,502 ) 7,812 2014-2017 WCMA 665 — 1 666 5,315 — (2,397 ) 2,918 2018 WCMA — — — — 8,958 (8,958 ) — — 2019 WCMA — — — — 557 (557 ) — — 2012 General Rate Case true-up 752 — — 752 7,731 (1 ) (3,631 ) 4,099 Cost of capital memorandum account (1,560 ) (1 ) — (1,561 ) (1,540 ) (7 ) — (1,547 ) Tax memorandum account 332 1 — 333 (6,585 ) (33 ) — (6,618 ) All others (2,451 ) 37 — (2,414 ) (1,794 ) (47 ) (128 ) (1,969 ) Total revenue accounts $ 8,287 (1,087 ) 2,626 9,826 $ 21,628 (9,275 ) (7,658 ) 4,695 Cost-recovery accounts: Water supply costs 5,899 1,222 1 7,122 5,912 1,049 (1,871 ) 5,090 Pension 2,985 (253 ) — 2,732 (233 ) 199 1,208 1,174 PRVMA — 1,219 (8 ) 1,211 — — — — All others 444 — — 444 870 2 (223 ) 649 Total cost-recovery accounts $ 9,328 2,188 (7 ) 11,509 $ 6,549 1,250 (886 ) 6,913 Total $ 17,615 1,101 2,619 21,335 $ 28,177 (8,025 ) (8,544 ) 11,608 Nine months ended September 30, 2020 Nine months ended September 30, 2019 Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Revenue accounts: Monterey WRAM $ 7,015 2,437 2,598 12,050 $ 6,847 3,994 (3,029 ) 7,812 2014-2017 WCMA 708 — (42 ) 666 7,750 — (4,832 ) 2,918 2018 WCMA — — — — 9,386 (9,386 ) — — 2019 WCMA — — — — — — — — 2012 General Rate Case true-up 752 — — 752 11,328 95 (7,324 ) 4,099 Cost of capital memorandum account (1,553 ) (8 ) — (1,561 ) (1,523 ) (24 ) — (1,547 ) Tax memorandum account (6,643 ) (2 ) 6,978 333 (6,504 ) (114 ) — (6,618 ) All others (2,219 ) (128 ) (67 ) (2,414 ) (1,735 ) 25 (259 ) (1,969 ) Total revenue accounts $ (1,940 ) 2,299 9,467 9,826 $ 25,549 (5,410 ) (15,444 ) 4,695 Cost-recovery accounts: Water supply costs 4,328 2,827 (33 ) 7,122 9,617 (754 ) (3,773 ) 5,090 Pension 2,449 261 22 2,732 (1,843 ) 582 2,435 1,174 PRVMA — 1,219 (8 ) 1,211 — — — — All others 446 2 (4 ) 444 1,090 8 (449 ) 649 Total cost-recovery accounts $ 7,223 4,309 (23 ) 11,509 $ 8,864 (164 ) (1,787 ) 6,913 Total $ 5,283 6,608 9,444 21,335 $ 34,413 (5,574 ) (17,231 ) 11,608 As of September 30, 2020 , the total balance in SJWC’s balancing and memorandum accounts combined, including interest, that have not been recorded into the financial statements was a net under-collection of $2,245 . All balancing accounts and memorandum-type accounts not included for recovery or refund in the current general rate case will be reviewed by the CPUC in SJWC’s next general rate case or at the time an individual account balance reaches a threshold of 2%

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	9 Months Ended
	Sep. 30, 2020
Regulatory Assets and Liabilities Disclosure [Abstract]
REGULARTORY ASSETS ANAD LIABILITIES	Regulatory Assets Regulatory assets are comprised of the following as of September 30, 2020 , and December 31, 2019 : September 30, 2020 December 31, 2019 Regulatory assets: Income tax temporary differences, net $ 3,363 2,433 Postretirement pensions and other medical benefits 77,906 73,525 Business combinations debt premium, net 23,114 25,020 Balancing and memorandum accounts, net 21,335 5,283 WRA 4,805 9,108 Other, net 6,451 5,048 Total regulatory assets, net in Consolidated Balance Sheets 136,974 120,417 Less: current regulatory asset, net 4,758 6,472 Total regulatory assets, net, less current portion $ 132,216 113,945

Business Combination Business C

Business Combination Business Combination	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
BUSINESS COMBINATION	Business Combination On October 9, 2019, SJW Group completed the merger with CTWS, a company that provides water service throughout Connecticut and Maine. In addition, CTWS has a real estate company in Connecticut which provides property management services. SJW Group acquired all of the outstanding stock of CTWS for $70.00 per share in cash (without interest and less any applicable withholding taxes). The total cash purchase price was approximately $838,476 , less cash received of $3,011 , and approximately $6,384 related to outstanding awards of restricted stock units and deferred share units assumed in connection with the merger. The following table summarizes the purchase price and recording of fair values of assets acquired and liabilities assumed as of the acquisition date and subsequent adjustments as of September 30, 2020 . Amounts Previously Recognized as of Acquisition Date (a) Measurement Period Adjustments Amounts Recognized as of Acquisition Date (as Adjusted) Assets acquired: Utility plant, net $ 750,703 $ — $ 750,703 Nonutility plant 848 — 848 Current assets 42,673 (1,167 ) 41,506 Investments 12,489 — 12,489 Regulatory assets and deferred charges, less current portion 83,132 (4,307 ) 78,825 Other intangible assets 17,181 — 17,181 Other assets 2,592 — 2,592 Goodwill 626,523 (1,222 ) 625,301 Total assets acquired 1,536,141 (6,696 ) 1,529,445 Liabilities assumed: Long-term debt 281,009 — 281,009 Current liabilities, including maturities of long-term debt 125,772 25 125,797 Deferred income taxes 107,789 (7,145 ) 100,644 Postretirement benefit plans 31,789 — 31,789 Contributions in aid of construction and construction advances 137,327 — 137,327 Other long-term liabilities 10,607 424 11,031 Total liabilities assumed 694,293 (6,696 ) 687,597 Assumed equity $ 841,848 $ — $ 841,848 ______________________________________ (a) As previously reported in the SJW Group’s 10-K for the period ended December 31, 2019. Other intangible assets primarily consists of customer relationships. The goodwill balance is primarily attributable to assembled workforce and diversification of markets both from a geographic and regulatory perspective. We do not expect the goodwill recognized in connection with the transaction will be deductible for income tax purposes. The company analyzed and revalued the acquired opening deferred tax asset and liability balances within the measurement period which resulted in a decrease to goodwill of $1,222 during the third quarter of 2020. There was no impact associated with the measurement period adjustments to the condensed consolidated statement of comprehensive income for the nine months ended September 30, 2020 .

Legal Proceedings

Legal Proceedings	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
LEGAL PROCEEDINGS	Legal Proceedings SJW Group is subject to ordinary routine litigation incidental to its business. There are no pending legal proceedings to which SJW Group or any of its subsidiaries is a party, or to which any of its properties is the subject, that are expected to have a material effect on SJW Group’s business, financial position, results of operations or cash flows.

General (Policies)

General (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting, Policy	The unaudited interim financial information has been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). The Notes to Consolidated Financial Statements in SJW Group’s 2019 Annual Report on Form 10-K should be read with the accompanying unaudited condensed consolidated financial statements.
New Accounting Pronouncements, Policy [Policy Text Block]	In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments,” and subsequent amendments. Topic 326 requires measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 was effective for SJW Group in the first quarter of fiscal 2020. The adoption of ASU 2016-13 did not have a material impact on the condensed consolidated financial statements. In August 2018, the FASB issued Accounting Standards Update (“ASU”) 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20: “Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans,” which aims to improve the overall usefulness of disclosure to financial statement users and reduce unnecessary costs to companies when preparing defined benefit plan disclosures. This update is effective for SJW Group’s Form 10-K for the year ending December 31, 2020. Retrospective adoption is required and early adoption is permitted. Management is currently evaluating the effect that the new standard will have on its defined benefit plan disclosures. In December 2019, the FASB issued ASU 2019-12, “Simplifying the Accounting for Income Taxes”, which simplifies the accounting for income taxes, eliminates certain exceptions within Topic 740, “Income Taxes”, and clarifies certain aspects of the current guidance to promote consistency among reporting entities. This update is effective for fiscal years beginning after December 15, 2021. Most amendments within the standard are required to be applied on a prospective basis, while certain amendments must be applied on a retrospective or modified retrospective basis. Management is currently evaluating the impacts of the provisions of ASU 2019-12 on our consolidated financial statements. In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting”. ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by the expected transition away from reference rates that are expected to be discontinued, such as LIBOR. ASU 2020-04 was effective upon issuance. Companies may elect to apply the guidance prospectively through December 31, 2022. Management is evaluating the effect that the new standard will have on its consolidated financial statements.
Revenue Recognition, Policy	Revenue Water sales are seasonal in nature and influenced by weather conditions. The timing of precipitation and climatic conditions can cause seasonal water consumption by customers to vary significantly. Due to the seasonal nature of the water business, the operating results for interim periods are not indicative of the operating results for a 12-month period. Revenue is generally higher in the warm, dry summer months when water usage and sales are greater, and lower in the winter months when cooler temperatures and increased precipitation curtail water usage and sales. The major streams of revenue for SJW Group are as follows: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Revenue from contracts with customers $ 167,045 130,777 $ 414,344 314,003 Alternative revenue programs, net 1,324 (11,912 ) 4,877 (14,218 ) Other balancing and memorandum accounts revenue, net (3,909 ) (6,221 ) 5,388 (9,229 ) Rental income 1,403 1,353 4,217 4,088 $ 165,863 113,997 $ 428,826 294,644
Earnings Per Share, Policy	Basic earnings per share is calculated using income available to common stockholders, divided by the weighted average number of shares outstanding during the period. Diluted earnings per share is calculated using income available to common stockholders divided by the weighted average number of shares of common stock including both shares outstanding and shares potentially issuable in connection with restricted common stock awards under SJW Group’s Long-Term Incentive Plan (as amended, the “Incentive Plan”), shares potentially issuable under the performance stock plans assumed through the business combination with Connecticut Water Service, Inc. (“CTWS”), and shares potentially issuable under the Employee Stock Purchase Plan (“ESPP”).
Utility Plant Depreciation, Policy	A portion of depreciation expense is allocated to administrative and general expense.

General Revenue (Tables)

General Revenue (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Major Streams of Revenue	The major streams of revenue for SJW Group are as follows: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Revenue from contracts with customers $ 167,045 130,777 $ 414,344 314,003 Alternative revenue programs, net 1,324 (11,912 ) 4,877 (14,218 ) Other balancing and memorandum accounts revenue, net (3,909 ) (6,221 ) 5,388 (9,229 ) Rental income 1,403 1,353 4,217 4,088 $ 165,863 113,997 $ 428,826 294,644

Equity Plans (Tables)

Equity Plans (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan	A summary of compensation costs charged to income and proceeds from the exercise of any restricted stock and similar instruments that are recorded to additional paid-in capital and common stock, by award type, are presented below for the three and nine months ended September 30, 2020 , and 2019 . Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Adjustments to additional paid-in capital and common stock for: Compensation costs charged to income: ESPP $ 152 140 $ 323 283 Restricted stock and deferred restricted stock 906 812 1,995 2,273 Total compensation costs charged to income $ 1,058 952 $ 2,318 2,556 ESPP proceeds $ 860 792 $ 1,830 1,603

Real Estate Investments (Tables

Real Estate Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Real Estate Investments, Net [Abstract]
Schedule of Real Estate Investments	The major components of real estate investments as of September 30, 2020 , and December 31, 2019 , are as follows: September 30, December 31, Land $ 14,168 14,168 Buildings and improvements 43,917 43,531 Subtotal 58,085 57,699 Less: accumulated depreciation and amortization 14,493 13,597 Total $ 43,592 44,102

Defined Benefit Plan (Tables)

Defined Benefit Plan (Tables)	9 Months Ended
	Sep. 30, 2020
Retirement Benefits [Abstract]
Schedule of Net Benefit Costs	The components of net periodic benefit costs for the defined benefit plans and other postretirement benefits for the three and nine months ended September 30, 2020 , and 2019 are as follows: Three months ended September 30, Nine months ended September 30, 2020 2019 2020 2019 Service cost $ 2,390 1,479 $ 7,170 4,437 Interest cost 2,860 2,113 8,580 6,338 Expected return on assets (4,126 ) (2,310 ) (12,429 ) (6,929 ) Unrecognized actuarial loss 1,296 1,056 3,888 3,168 Amortization of prior service cost 39 61 115 184 $ 2,459 2,399 $ 7,324 7,198
Schedule of Allocation of Plan Assets	The following tables summarize the fair values of plan assets by major categories as of September 30, 2020 , and December 31, 2019 : Fair Value Measurements at September 30, 2020 Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents $ 7,921 7,921 — — Equity securities (a) 159,687 155,850 3,837 — Fixed income (b) 101,653 34,806 66,847 — Total $ 269,261 198,577 70,684 — ______________________________________ (a) Actively managed portfolio of equity securities with the goal to exceed the benchmark performance (b) Actively managed portfolio of fixed income securities with the goal to exceed the benchmark performance Fair Value Measurements at December 31, 2019 Quoted Prices in Active Markets for Identical Assets Significant Observable Inputs Significant Unobservable Inputs Asset Category Total (Level 1) (Level 2) (Level 3) Cash and cash equivalents $ 11,801 11,801 — — Equity securities (a) 157,050 149,265 7,785 — Fixed income (b) 91,896 31,686 60,210 — Total $ 260,747 192,752 67,995 —

Segment and Non-Tariffed Busi_2

Segment and Non-Tariffed Business Reporting (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables set forth information relating to SJW Group’s reportable segments and distribution of regulated and non-tariffed business activities within the reportable segments. Certain allocated assets, such as goodwill, revenue and expenses have been included in the reportable segment amounts. Other business activity of SJW Group not included in the reportable segments is included in the “All Other” category. For Three Months Ended September 30, 2020 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 161,646 2,814 1,403 — 161,646 4,217 165,863 Operating expense 119,885 2,161 961 973 119,885 4,095 123,980 Operating income (loss) 41,761 653 442 (973 ) 41,761 122 41,883 Net income (loss) 25,053 827 310 (97 ) 25,053 1,040 26,093 Depreciation and amortization 21,782 116 296 223 21,782 635 22,417 Interest on long-term debt and other interest expense 8,112 — — 5,062 8,112 5,062 13,174 Provision for income taxes 9,450 179 105 (5,156 ) 9,450 (4,872 ) 4,578 Assets $ 3,131,778 8,589 45,980 73,367 3,131,778 127,936 3,259,714 For Three Months Ended September 30, 2019 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 110,218 2,426 1,353 — 110,218 3,779 113,997 Operating expense 89,924 1,636 935 4,418 89,924 6,989 96,913 Operating income (loss) 20,294 790 418 (4,418 ) 20,294 (3,210 ) 17,084 Net income (loss) 10,964 555 304 (2,345 ) 10,964 (1,486 ) 9,478 Depreciation and amortization 14,712 111 299 — 14,712 410 15,122 Interest on long-term debt and other interest expense 6,044 — — 544 6,044 544 6,588 Provision for income taxes 2,912 216 95 (658 ) 2,912 (347 ) 2,565 Assets $ 1,556,049 5,899 46,160 414,274 1,556,049 466,333 2,022,382 For Nine Months Ended September 30, 2020 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 416,085 8,524 4,217 — 416,085 12,741 428,826 Operating expense 323,087 5,281 2,642 4,436 323,087 12,359 335,446 Operating income (loss) 92,998 3,243 1,575 (4,436 ) 92,998 382 93,380 Net income (loss) 53,117 3,178 1,141 (9,205 ) 53,117 (4,886 ) 48,231 Depreciation and amortization 64,654 332 896 670 64,654 1,898 66,552 Interest on long-term debt and other interest expense 24,575 — — 15,063 24,575 15,063 39,638 Provision for income taxes 16,101 909 361 (8,145 ) 16,101 (6,875 ) 9,226 Assets $ 3,131,778 8,589 45,980 73,367 3,131,778 127,936 3,259,714 For Nine Months Ended September 30, 2019 Water Utility Services Real Estate Services All Other* SJW Group Regulated Non-tariffed Non-tariffed Non-tariffed Regulated Non-tariffed Total Operating revenue $ 285,138 5,418 4,088 — 285,138 9,506 294,644 Operating expense 226,073 3,833 2,834 10,441 226,073 17,108 243,181 Operating income (loss) 59,065 1,585 1,254 (10,441 ) 59,065 (7,602 ) 51,463 Net income (loss) 30,726 1,127 1,284 (4,248 ) 30,726 (1,837 ) 28,889 Depreciation and amortization 44,159 313 896 — 44,159 1,209 45,368 Interest on long-term debt and other interest expense 17,434 — — 1,659 17,434 1,659 19,093 Provision for income taxes 9,142 438 445 (1,223 ) 9,142 (340 ) 8,802 Assets $ 1,556,049 5,899 46,160 414,274 1,556,049 466,333 2,022,382 * The “All Other” category for the nine months ended September 30, 2020 , includes the accounts of SJW Group, SJWNE LLC and CTWS on a stand-alone basis. For the three months ended September 30, 2019 , the “All Other” category includes the accounts of SJW Group and Hydro Sub, Inc. on a stand-alone basis. For the three months ended September 30, 2019 , Hydro Sub, Inc. had no recorded revenue or expenses and as of September 30, 2019 held no assets and incurred no liabilities. Hydro Sub. Inc. was a subsidiary created solely to facilitate the merger with CTWS and was dissolved following the completion of merger in October 2019.

Balancing and Memorandum Acco_2

Balancing and Memorandum Accounts (Tables)	9 Months Ended
	Sep. 30, 2020
Regulated Operations [Abstract]
Public Utilities General Disclosures	Three months ended September 30, 2020 Three months ended September 30, 2019 Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Revenue accounts: Monterey WRAM $ 10,549 (1,124 ) 2,625 12,050 $ 8,986 328 (1,502 ) 7,812 2014-2017 WCMA 665 — 1 666 5,315 — (2,397 ) 2,918 2018 WCMA — — — — 8,958 (8,958 ) — — 2019 WCMA — — — — 557 (557 ) — — 2012 General Rate Case true-up 752 — — 752 7,731 (1 ) (3,631 ) 4,099 Cost of capital memorandum account (1,560 ) (1 ) — (1,561 ) (1,540 ) (7 ) — (1,547 ) Tax memorandum account 332 1 — 333 (6,585 ) (33 ) — (6,618 ) All others (2,451 ) 37 — (2,414 ) (1,794 ) (47 ) (128 ) (1,969 ) Total revenue accounts $ 8,287 (1,087 ) 2,626 9,826 $ 21,628 (9,275 ) (7,658 ) 4,695 Cost-recovery accounts: Water supply costs 5,899 1,222 1 7,122 5,912 1,049 (1,871 ) 5,090 Pension 2,985 (253 ) — 2,732 (233 ) 199 1,208 1,174 PRVMA — 1,219 (8 ) 1,211 — — — — All others 444 — — 444 870 2 (223 ) 649 Total cost-recovery accounts $ 9,328 2,188 (7 ) 11,509 $ 6,549 1,250 (886 ) 6,913 Total $ 17,615 1,101 2,619 21,335 $ 28,177 (8,025 ) (8,544 ) 11,608 Nine months ended September 30, 2020 Nine months ended September 30, 2019 Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Beginning Balance Regulatory Asset Increase (Decrease) Refunds (Collections) Adjustments Ending Balance Revenue accounts: Monterey WRAM $ 7,015 2,437 2,598 12,050 $ 6,847 3,994 (3,029 ) 7,812 2014-2017 WCMA 708 — (42 ) 666 7,750 — (4,832 ) 2,918 2018 WCMA — — — — 9,386 (9,386 ) — — 2019 WCMA — — — — — — — — 2012 General Rate Case true-up 752 — — 752 11,328 95 (7,324 ) 4,099 Cost of capital memorandum account (1,553 ) (8 ) — (1,561 ) (1,523 ) (24 ) — (1,547 ) Tax memorandum account (6,643 ) (2 ) 6,978 333 (6,504 ) (114 ) — (6,618 ) All others (2,219 ) (128 ) (67 ) (2,414 ) (1,735 ) 25 (259 ) (1,969 ) Total revenue accounts $ (1,940 ) 2,299 9,467 9,826 $ 25,549 (5,410 ) (15,444 ) 4,695 Cost-recovery accounts: Water supply costs 4,328 2,827 (33 ) 7,122 9,617 (754 ) (3,773 ) 5,090 Pension 2,449 261 22 2,732 (1,843 ) 582 2,435 1,174 PRVMA — 1,219 (8 ) 1,211 — — — — All others 446 2 (4 ) 444 1,090 8 (449 ) 649 Total cost-recovery accounts $ 7,223 4,309 (23 ) 11,509 $ 8,864 (164 ) (1,787 ) 6,913 Total $ 5,283 6,608 9,444 21,335 $ 34,413 (5,574 ) (17,231 ) 11,608

Regulatory Assets and Liabili_2

Regulatory Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Regulatory Assets and Liabilities Disclosure [Abstract]
Schedule of Regulatory Assets	Regulatory assets are comprised of the following as of September 30, 2020 , and December 31, 2019 : September 30, 2020 December 31, 2019 Regulatory assets: Income tax temporary differences, net $ 3,363 2,433 Postretirement pensions and other medical benefits 77,906 73,525 Business combinations debt premium, net 23,114 25,020 Balancing and memorandum accounts, net 21,335 5,283 WRA 4,805 9,108 Other, net 6,451 5,048 Total regulatory assets, net in Consolidated Balance Sheets 136,974 120,417 Less: current regulatory asset, net 4,758 6,472 Total regulatory assets, net, less current portion $ 132,216 113,945

Business Combination (Tables)

Business Combination (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The following table summarizes the purchase price and recording of fair values of assets acquired and liabilities assumed as of the acquisition date and subsequent adjustments as of September 30, 2020 . Amounts Previously Recognized as of Acquisition Date (a) Measurement Period Adjustments Amounts Recognized as of Acquisition Date (as Adjusted) Assets acquired: Utility plant, net $ 750,703 $ — $ 750,703 Nonutility plant 848 — 848 Current assets 42,673 (1,167 ) 41,506 Investments 12,489 — 12,489 Regulatory assets and deferred charges, less current portion 83,132 (4,307 ) 78,825 Other intangible assets 17,181 — 17,181 Other assets 2,592 — 2,592 Goodwill 626,523 (1,222 ) 625,301 Total assets acquired 1,536,141 (6,696 ) 1,529,445 Liabilities assumed: Long-term debt 281,009 — 281,009 Current liabilities, including maturities of long-term debt 125,772 25 125,797 Deferred income taxes 107,789 (7,145 ) 100,644 Postretirement benefit plans 31,789 — 31,789 Contributions in aid of construction and construction advances 137,327 — 137,327 Other long-term liabilities 10,607 424 11,031 Total liabilities assumed 694,293 (6,696 ) 687,597 Assumed equity $ 841,848 $ — $ 841,848

General - Schedule of Major Str

General - Schedule of Major Streams of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Revenue from contracts with customers	$ 167,045	$ 130,777	$ 414,344	$ 314,003
Alternative revenue programs, net	1,324	(11,912)	4,877	(14,218)
Other balancing and memorandum accounts revenue, net	(3,909)	(6,221)	5,388	(9,229)
Rental income	1,403	1,353	4,217	4,088
Total revenues	$ 165,863	$ 113,997	$ 428,826	$ 294,644

General - Earnings Per Share (D

General - Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restricted Stock and Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive restricted common stock units excluded from computation of earnings per share (shares)	1,029	524	20,220	10,158

General - Depreciation (Details

General - Depreciation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
General and Administrative Expense
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation	$ 658	$ 663	$ 2,128	$ 1,995

Equity Plans (Details)

Equity Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs charged to income:	$ 1,058	$ 952	$ 2,318	$ 2,556
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments granted (shares)	761	0	43,474	26,565
Grant date fair value of equity instruments granted (usd per share)	$ 58.63	$ 0	$ 63.87	$ 51.42
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity instruments granted (shares)	58	0	24,777	30,401
Grant date fair value of equity instruments granted (usd per share)	$ 62.95	$ 0	$ 65.02	$ 60.46
Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target vesting percentage			0.00%
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target vesting percentage			150.00%
Market-based RSU [Member] | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target vesting percentage			0.00%
Market-based RSU [Member] | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target vesting percentage			200.00%
Restricted stock and deferred restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs charged to income:	$ 906	$ 812	$ 1,995	$ 2,273
Unrecognized compensation costs	$ 4,987		$ 4,987
Recognition period for unrecognized compensation cost			1 year 10 months 9 days
Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable upon exercise of Incentive Plan awards (shares)			182,367
Remaining shares available for issuance under the Incentive Plan (shares)	743,038		743,038
CTWS Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issuable upon exercise of Incentive Plan awards (shares)			66,430
Employee Stock Purchase Plan (ESPP)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation costs charged to income:	$ 152	140	$ 323	283
ESPP proceeds	860	792	1,830	1,603
Unrecognized compensation costs	$ 116		$ 116
Purchase price of common stock under ESPP (percent)			85.00%
Maximum percentage of base compensation employees can designate for stock purchases under ESPP (percent)	10.00%		10.00%
Plan expense	$ 85	$ 82	$ 244	$ 223
Employee Stock Purchase Plan (ESPP) | Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance under the plan (shares)	400,000		400,000

Real Estate Investments (Detail

Real Estate Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Investments [Line Items]
Land	$ 14,168		$ 14,168		$ 14,168
Buildings and improvements	43,917		43,917		43,531
Subtotal	58,085		58,085		57,699
Less accumulated depreciation and amortization	14,493		14,493		13,597
Total	43,592		43,592		$ 44,102
Proceeds from sale of real estate held-for-investment				$ 745
Gain on sale of real estate investments	$ 1,050	$ 0	$ 1,050	745
Restricted Cash		$ 750		750
Minimum
Schedule of Investments [Line Items]
Estimated useful life			7 years
Maximum
Schedule of Investments [Line Items]
Estimated useful life			39 years
San Jose Water Company [Member]
Schedule of Investments [Line Items]
Proceeds from sale of real estate held-for-investment			$ 1,075
Gain on sale of real estate investments			1,048
Real Estate Selling Expenses			$ 22
Parent [Member]
Schedule of Investments [Line Items]
Gain on sale of real estate investments				521
Noncontrolling Interest [Member]
Schedule of Investments [Line Items]
Gain on sale of real estate investments				$ 224
SJW Land Company [Member] | Partnership Interest [Member]
Schedule of Investments [Line Items]
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest			70.00%

Defined Benefit Plan (Details)

Defined Benefit Plan (Details) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2020		Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019	Dec. 31, 2019
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 2,390,000		$ 1,479,000	$ 7,170,000		$ 4,437,000
Interest cost	2,860,000		2,113,000	8,580,000		6,338,000
Expected return on assets	(4,126,000)		(2,310,000)	(12,429,000)		(6,929,000)
Unrecognized actuarial loss	1,296,000		1,056,000	3,888,000		3,168,000
Amortization of prior service cost	39,000		61,000	115,000		184,000
Net periodic benefit cost	2,459,000		$ 2,399,000	7,324,000		$ 7,198,000
Plan Assets [Abstract]
Fair value of plan assets	269,261,000			269,261,000			$ 260,747,000
Employer Contributions [Abstract]
Estimated employer contributions for the current fiscal year	14,594,000			14,594,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	9,360,000			9,360,000
Quoted Prices in Active Markets for Identical Assets
Plan Assets [Abstract]
Fair value of plan assets	198,577,000			198,577,000			192,752,000
Significant Observable Inputs
Plan Assets [Abstract]
Fair value of plan assets	70,684,000			70,684,000			67,995,000
Significant Unobservable Inputs
Plan Assets [Abstract]
Fair value of plan assets	0			0			0
Cash and cash equivalents
Plan Assets [Abstract]
Fair value of plan assets	7,921,000			7,921,000			11,801,000
Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets
Plan Assets [Abstract]
Fair value of plan assets	7,921,000			7,921,000			11,801,000
Cash and cash equivalents | Significant Observable Inputs
Plan Assets [Abstract]
Fair value of plan assets	0			0			0
Cash and cash equivalents | Significant Unobservable Inputs
Plan Assets [Abstract]
Fair value of plan assets	0			0			0
Actively Managed | Equity securities (a)
Plan Assets [Abstract]
Fair value of plan assets	159,687,000	[1]		159,687,000	[1]		157,050,000	[2]
Actively Managed | Equity securities (a) | Quoted Prices in Active Markets for Identical Assets
Plan Assets [Abstract]
Fair value of plan assets	155,850,000	[1]		155,850,000	[1]		149,265,000	[2]
Actively Managed | Equity securities (a) | Significant Observable Inputs
Plan Assets [Abstract]
Fair value of plan assets	3,837,000	[1]		3,837,000	[1]		7,785,000	[2]
Actively Managed | Equity securities (a) | Significant Unobservable Inputs
Plan Assets [Abstract]
Fair value of plan assets	0	[1]		0	[1]		0	[2]
Fixed Income | Fixed income (b)
Plan Assets [Abstract]
Fair value of plan assets	101,653,000	[3]		101,653,000	[3]		91,896,000	[4]
Fixed Income | Fixed income (b) | Quoted Prices in Active Markets for Identical Assets
Plan Assets [Abstract]
Fair value of plan assets	34,806,000	[3]		34,806,000	[3]		31,686,000	[4]
Fixed Income | Fixed income (b) | Significant Observable Inputs
Plan Assets [Abstract]
Fair value of plan assets	66,847,000	[3]		66,847,000	[3]		60,210,000	[4]
Fixed Income | Fixed income (b) | Significant Unobservable Inputs
Plan Assets [Abstract]
Fair value of plan assets	$ 0	[3]		$ 0	[3]		$ 0	[4]
[1]	Actively managed portfolio of equity securities with the goal to exceed the benchmark performance
[2]
[3]	Actively managed portfolio of fixed income securities with the goal to exceed the benchmark performance
[4]

Segment and Non-Tariffed Busi_3

Segment and Non-Tariffed Business Reporting (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)subsidiary	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of subsidiaries | subsidiary				4
Operating revenue		$ 165,863	$ 113,997	$ 428,826	$ 294,644
Operating expense		123,980	96,913	335,446	243,181
Operating income (loss)		41,883	17,084	93,380	51,463
Net income (loss)		26,093	9,478	48,231	28,889
Depreciation and amortization		22,417	15,122	66,552	45,368
Interest on long-term debt and other interest expense		13,174	6,588	39,638	19,093
Provision for income taxes		4,578	2,565	9,226	8,802
Assets		3,259,714	2,022,382	3,259,714	2,022,382	$ 3,132,470
Water Utility Services | Regulated
Segment Reporting Information [Line Items]
Operating revenue		161,646	110,218	416,085	285,138
Operating expense		119,885	89,924	323,087	226,073
Operating income (loss)		41,761	20,294	92,998	59,065
Net income (loss)		25,053	10,964	53,117	30,726
Depreciation and amortization		21,782	14,712	64,654	44,159
Interest on long-term debt and other interest expense		8,112	6,044	24,575	17,434
Provision for income taxes		9,450	2,912	16,101	9,142
Assets		3,131,778	1,556,049	3,131,778	1,556,049
Water Utility Services | Non-tariffed
Segment Reporting Information [Line Items]
Operating revenue		2,814	2,426	8,524	5,418
Operating expense		2,161	1,636	5,281	3,833
Operating income (loss)		653	790	3,243	1,585
Net income (loss)		827	555	3,178	1,127
Depreciation and amortization		116	111	332	313
Interest on long-term debt and other interest expense		0	0	0	0
Provision for income taxes		179	216	909	438
Assets		8,589	5,899	8,589	5,899
Real Estate Services | Non-tariffed
Segment Reporting Information [Line Items]
Operating revenue		1,403	1,353	4,217	4,088
Operating expense		961	935	2,642	2,834
Operating income (loss)		442	418	1,575	1,254
Net income (loss)		310	304	1,141	1,284
Depreciation and amortization		296	299	896	896
Interest on long-term debt and other interest expense		0	0	0	0
Provision for income taxes		105	95	361	445
Assets		45,980	46,160	45,980	46,160
All Other | Non-tariffed
Segment Reporting Information [Line Items]
Operating revenue	[1]	0	0	0	0
Operating expense	[1]	973	4,418	4,436	10,441
Operating income (loss)	[1]	(973)	(4,418)	(4,436)	(10,441)
Net income (loss)	[1]	(97)	(2,345)	(9,205)	(4,248)
Depreciation and amortization	[1]	223	0	670	0
Interest on long-term debt and other interest expense	[1]	5,062	544	15,063	1,659
Provision for income taxes	[1]	(5,156)	(658)	(8,145)	(1,223)
Assets	[1]	73,367	414,274	73,367	414,274
SJW Group | Regulated
Segment Reporting Information [Line Items]
Operating revenue		161,646	110,218	416,085	285,138
Operating expense		119,885	89,924	323,087	226,073
Operating income (loss)		41,761	20,294	92,998	59,065
Net income (loss)		25,053	10,964	53,117	30,726
Depreciation and amortization		21,782	14,712	64,654	44,159
Interest on long-term debt and other interest expense		8,112	6,044	24,575	17,434
Provision for income taxes		9,450	2,912	16,101	9,142
Assets		3,131,778	1,556,049	3,131,778	1,556,049
SJW Group | Non-tariffed
Segment Reporting Information [Line Items]
Operating revenue		4,217	3,779	12,741	9,506
Operating expense		4,095	6,989	12,359	17,108
Operating income (loss)		122	(3,210)	382	(7,602)
Net income (loss)		1,040	(1,486)	(4,886)	(1,837)
Depreciation and amortization		635	410	1,898	1,209
Interest on long-term debt and other interest expense		5,062	544	15,063	1,659
Provision for income taxes		(4,872)	(347)	(6,875)	(340)
Assets		$ 127,936	$ 466,333	$ 127,936	$ 466,333
[1]	* The “All Other” category for the nine months ended September 30, 2020 , includes the accounts of SJW Group, SJWNE LLC and CTWS on a stand-alone basis. For the three months ended September 30, 2019 , the “All Other” category includes the accounts of SJW Group and Hydro Sub, Inc. on a stand-alone basis. For the three months ended September 30, 2019 , Hydro Sub, Inc. had no recorded revenue or expenses and as of September 30, 2019 held no assets and incurred no liabilities. Hydro Sub. Inc. was a subsidiary created solely to facilitate the merger with CTWS and was dissolved following the completion of merger in October 2019.

Long-Term Liabilities and Ban_2

Long-Term Liabilities and Bank Borrowings (Details) - USD ($)

Aug. 11, 2020

May 11, 2020

Mar. 12, 2020

Mar. 11, 2020

Feb. 03, 2020

Sep. 30, 2020

May 29, 2020

May 28, 2020

May 10, 2020

Apr. 29, 2020

Apr. 28, 2020

Dec. 31, 2019

Dec. 19, 2019

Debt Instrument [Line Items]

Long-term Debt

$ 1,379,555,000

$ 1,305,869,000

Connecticut Water Company [Member] | Senior Notes [Member]

Debt Instrument [Line Items]

Principal Debt Sold

$ 35,000,000

Debt Instrument, Interest Rate, Stated Percentage

3.51%

Ratio of Indebtedness to Capital

0.60

Maine Water Company [Member]

Debt Instrument [Line Items]

Increase (Decrease) in Restricted Cash

$ (886,000)

$ (4,114,000)

Maine Water Company [Member] | Public Utility, Bonds [Member]

Debt Instrument [Line Items]

Ratio of Indebtedness to Capital

0.65

Maine Water Company [Member] | Public Utility, Bonds [Member] | State Revolving Fund Loans Series S [Member]

Debt Instrument [Line Items]

Debt Instrument, Interest Rate, Stated Percentage

1.00%

Long-term Debt

$ 5,000,000

Parent [Member] | Senior Notes [Member]

Debt Instrument [Line Items]

Principal Debt Sold

$ 50,000,000

Debt Instrument, Interest Rate, Stated Percentage

2.47%

Revolving Credit Facility [Member] | Chase Bank, N.A. [Member] | SJW Corp. and SJW Land Company [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$ 0

$ 15,000,000

Revolving Credit Facility [Member] | Chase Bank, N.A. [Member] | San Jose Water Company [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$ 140,000,000

$ 125,000,000

Line of Credit Facility, Increase in Maximum Borrowing Capacity

15,000,000

Revolving Credit Facility - Temporary [Member] | Chase Bank, N.A. [Member] | San Jose Water Company [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$ 50,000,000

Connecticut Water Service, Inc. [Member] | Revolving Credit Facility [Member] | CoBank [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Line of Credit Facility, Maximum Borrowing Capacity

$ 40,000,000

$ 15,000,000

Line of Credit Facility, Increase in Maximum Borrowing Capacity

$ 25,000,000

Fed Funds Effective Rate | Revolving Credit Facility - Temporary [Member] | Chase Bank, N.A. [Member] | San Jose Water Company [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Debt Instrument, Basis Spread on Variable Rate

0.50%

London Interbank Offered Rate (LIBOR) | Revolving Credit Facility - Temporary [Member] | Chase Bank, N.A. [Member] | San Jose Water Company [Member] | Line of Credit [Member]

Debt Instrument [Line Items]

Debt Instrument, Basis Spread on Variable Rate

1.00%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 4,578	$ 2,565	$ 9,226	$ 8,802
Effective Income Tax Rate Reconciliation, Percent	15.00%	21.00%	16.00%	23.00%
Unrecognized Tax Benefits	$ 6,594		$ 6,594		$ 3,834

Fair Value Measurement (Details

Fair Value Measurement (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	$ 269,261	$ 260,747
Life Insurance, Corporate or Bank Owned, Amount	7,497	7,086
Cash Surrender Value of Life Insurance	3,913	3,829
Long-term Debt	1,379,555	1,305,869
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	198,577	192,752
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	70,684	67,995
Long-term debt, fair value	1,575,067	1,396,205
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Supplemental Employee Retirement Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	2,874	3,183
Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	2,874	3,183
Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Money Market Funds [Member] | Supplemental Employee Retirement Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	38	20
Money Market Funds [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	38	20
Money Market Funds [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Money Market Funds [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Mutual Fund [Member] | Supplemental Employee Retirement Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	2,021	834
Mutual Fund [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	2,021	834
Mutual Fund [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Mutual Fund [Member] | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Fixed Income | Supplemental Employee Retirement Plan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	815	2,329
Fixed Income | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	815	2,329
Fixed Income | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	0	0
Fixed Income | Supplemental Employee Retirement Plan [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of plan assets	$ 0	$ 0

Regulatory Rate Filings (Detail

Regulatory Rate Filings (Details) - USD ($)

Oct. 28, 2020

Aug. 27, 2020

Jun. 17, 2020

Jan. 22, 2020

Jan. 20, 2020

Dec. 20, 2019

Nov. 20, 2019

Oct. 01, 2019

Sep. 30, 2019

Feb. 01, 2019

Jan. 28, 2019

Sep. 14, 2018

Sep. 30, 2020

Sep. 30, 2019

Sep. 30, 2020

Sep. 30, 2019

Apr. 24, 2020

Feb. 07, 2020

Jan. 28, 2020

Dec. 06, 2019

Oct. 18, 2019

Aug. 01, 2019

Jul. 26, 2019

Public Utilities, General Disclosures [Line Items]

Regulatory Asset Increase (Decrease)

$ (1,087,000)

$ (9,275,000)

$ 2,299,000

$ (5,410,000)

OII No. 18-09-003 Settlement Agreement

Public Utilities, General Disclosures [Line Items]

Customer Credit Refund

$ 350,000

OII No. 18-09-003 Settlement Agreement | Minimum

Public Utilities, General Disclosures [Line Items]

Customer Credit Refund

1,757,000

Avon Water Company [Member]

Public Utilities, General Disclosures [Line Items]

Authorized WICA Surcharge, Percentage

9.31%

9.31%

San Jose Water Company [Member]

Public Utilities, General Disclosures [Line Items]

CPED Calculated Double-Billing Refund

$ 4,935,000

San Jose Water Company [Member] | Minimum

Public Utilities, General Disclosures [Line Items]

CPED Proposed Penalty, Per Offense, Per Day

500

San Jose Water Company [Member] | Maximum

Public Utilities, General Disclosures [Line Items]

CPED Proposed Penalty, Per Offense, Per Day

50,000

San Jose Water Company [Member] | CPED Calculated Refund 2014-2016

Public Utilities, General Disclosures [Line Items]

CPED Calculated Service Charge Refund

2,061,000

San Jose Water Company [Member] | CPED Calculated Refund 1987-2013

Public Utilities, General Disclosures [Line Items]

CPED Calculated Service Charge Refund

$ 1,990,000

San Jose Water Company [Member] | OII No. 18-09-003 Settlement Agreement

Public Utilities, General Disclosures [Line Items]

Utility Plant Investment Commitment

5,000,000

San Jose Water Company [Member] | OII No. 18-09-003 Settlement Agreement | Maximum

Public Utilities, General Disclosures [Line Items]

Customer Credit Refund

2,100,000

San Jose Water Company [Member] | Advice Letter No. 545 [Member]

Public Utilities, General Disclosures [Line Items]

Customer Credit Refund

$ (5.52)

San Jose Water Company [Member] | Advice Letter No. 534 [Member]

Public Utilities, General Disclosures [Line Items]

Memorandum Account, Requested Recovery

$ 1,243,000

San Jose Water Company [Member] | Advice Letter No. 548 [Member]

Public Utilities, General Disclosures [Line Items]

Memorandum Account, Requested Recovery

$ 1,224,000

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 1,219,000

San Jose Water Company [Member] | Advice Letter No. 537

Public Utilities, General Disclosures [Line Items]

Memorandum Account, Requested Refund, Monthly Amount

$ 20.84

San Jose Water Company [Member] | Advice Letter No. 541 [Member]

Public Utilities, General Disclosures [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 8,600,000

Public Utilities, Requested Rate Increase (Decrease), Percentage

2.28%

San Jose Water Company [Member] | Application No. 19-12-002 [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Rate Filings, Requested Rate Increase, Year One

$ 2,315,000

Regulatory Rate Filings, Requested Rate Increase as Percentage of Total Revenue at Time of Request, Year One

0.61%

Regulatory Rate Filings, Requested Rate Increase, Year Two

$ 3,960,000

Regulatory Rate Filings, Proposed Rate Increase, Percent of Authorized Revenue, Year Two

1.04%

Regulatory Rate Filings, Requested Rate Increase, Year Three

$ 2,510,000

Regulatory Rate Filings, Requested Rate Increase, Percent of Authorized Revenue, Year Three

0.65%

Regulatory Rate Filings, Requested Rate Increase, Year Four

$ 341,000

Regulatory Rate Filings, Requested Rate Increase, Percent of Authorized Revenue, Year Four

0.09%

San Jose Water Company [Member] | Cost Of Capital Filings [Member]

Public Utilities, General Disclosures [Line Items]

Regulatory Rate Filings, Requested Deferment Period

1 year

Connecticut Water Company [Member]

Public Utilities, General Disclosures [Line Items]

Authorized WICA Surcharge, Percentage

5.75%

5.75%

Requested WICA Surcharge Increase (Decrease), Percentage

(0.09%)

2.60%

Requested WICA Surcharge, Percentage

5.75%

5.84%

SJWTX, Inc. [Member]

Public Utilities, General Disclosures [Line Items]

Authorized Regulatory Surcharge, Per Thousand Gallons

$ 2.02

$ 2.19

$ 1.05

$ 0.95

Authorized Regulatory Base Charge, Per Residential Account

$ 3.04

Maine Water Company [Member]

Public Utilities, General Disclosures [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 371,000

$ 221,000

Public Utilities, Requested Rate Increase (Decrease), Percentage

14.70%

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 198,000

Public Utilities, Approved Rate Increase (Decrease), Percentage, Step Increase 1

9.80%

Public Utilities, Approved Rate Increase (Decrease), Percentage, Step Increase 2

3.51%

Public Utilities, Approved Rate Increase (Decrease), Percentage

13.31%

Maine Water Company [Member] | Minimum

Public Utilities, General Disclosures [Line Items]

Requested WISC Surcharge Increase (Decrease), Percentage

1.76%

Maine Water Company [Member] | Maximum

Public Utilities, General Disclosures [Line Items]

Requested WISC Surcharge Increase (Decrease), Percentage

3.00%

Cost of capital memorandum account

Public Utilities, General Disclosures [Line Items]

Regulatory Asset Increase (Decrease)

$ (1,000)

$ (7,000)

$ (8,000)

$ (24,000)

Subsequent Event [Member] | Connecticut Water Company [Member]

Public Utilities, General Disclosures [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 956,000

Requested WICA Surcharge, Percentage

6.85%

Subsequent Event [Member] | Connecticut Water Company [Member] | WICA [Member]

Public Utilities, General Disclosures [Line Items]

Requested WICA Surcharge Increase (Decrease), Percentage

1.11%

Balancing and Memorandum Acco_3

Balancing and Memorandum Accounts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	$ 8,287	$ 21,628	$ (1,940)	$ 25,549
Balancing and Memorandum Revenue Account, Increase (Decrease)	(1,087)	(9,275)	2,299	(5,410)
Refunds (Collections) Adjustments	2,626	(7,658)	9,467	(15,444)
Ending Balance	9,826	4,695	9,826	4,695
Balancing and Memorandum Cost Recovery Account [Roll Forward]
Beginning Balance	9,328	6,549	7,223	8,864
Regulatory Asset Increase (Decrease)	2,188	1,250	4,309	(164)
Refunds (Collections) Adjustments	(7)	(886)	(23)	(1,787)
Ending Balance	11,509	6,913	11,509	6,913
Balancing and Memorandum Account [Roll Forward]
Beginning Balance	17,615	28,177	5,283	34,413
Regulatory Asset Increase (Decrease)	1,101	(8,025)	6,608	(5,574)
Refunds (Collections)	2,619	(8,544)	9,444	(17,231)
Ending Balance	21,335	11,608	21,335	11,608
Total balance, net under-collection amount	$ 2,245		$ 2,245
Authorized revenue, threshold percentage	2.00%		2.00%
Monterey WRAM
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	$ 10,549	8,986	$ 7,015	6,847
Balancing and Memorandum Revenue Account, Increase (Decrease)	(1,124)	328	2,437	3,994
Refunds (Collections) Adjustments	2,625	(1,502)	2,598	(3,029)
Ending Balance	12,050	7,812	12,050	7,812
2014-2017 WCMA
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	665	5,315	708	7,750
Balancing and Memorandum Revenue Account, Increase (Decrease)	0	0	0	0
Refunds (Collections) Adjustments	1	(2,397)	(42)	(4,832)
Ending Balance	666	2,918	666	2,918
2018 WCMA
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	0	8,958	0	9,386
Balancing and Memorandum Revenue Account, Increase (Decrease)	0	(8,958)	0	(9,386)
Refunds (Collections) Adjustments	0	0	0	0
Ending Balance	0	0	0	0
2019 WCMA
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	0	557	0	0
Balancing and Memorandum Revenue Account, Increase (Decrease)	0	(557)	0	0
Refunds (Collections) Adjustments	0	0	0	0
Ending Balance	0	0	0	0
2012 General Rate Case true-up
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	752	7,731	752	11,328
Balancing and Memorandum Revenue Account, Increase (Decrease)	0	(1)	0	95
Refunds (Collections) Adjustments	0	(3,631)	0	(7,324)
Ending Balance	752	4,099	752	4,099
Cost of capital memorandum account
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	(1,560)	(1,540)	(1,553)	(1,523)
Balancing and Memorandum Revenue Account, Increase (Decrease)	(1)	(7)	(8)	(24)
Refunds (Collections) Adjustments	0	0	0	0
Ending Balance	(1,561)	(1,547)	(1,561)	(1,547)
Tax memorandum account
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	332	(6,585)	(6,643)	(6,504)
Balancing and Memorandum Revenue Account, Increase (Decrease)	1	(33)	(2)	(114)
Refunds (Collections) Adjustments	0	0	6,978	0
Ending Balance	333	(6,618)	333	(6,618)
All others
Balancing and Memorandum Revenue Account [Roll Forward]
Beginning Balance	(2,451)	(1,794)	(2,219)	(1,735)
Balancing and Memorandum Revenue Account, Increase (Decrease)	37	(47)	(128)	25
Refunds (Collections) Adjustments	0	(128)	(67)	(259)
Ending Balance	(2,414)	(1,969)	(2,414)	(1,969)
Balancing and Memorandum Cost Recovery Account [Roll Forward]
Beginning Balance	444	870	446	1,090
Regulatory Asset Increase (Decrease)	0	2	2	8
Refunds (Collections) Adjustments	0	(223)	(4)	(449)
Ending Balance	444	649	444	649
Water supply costs
Balancing and Memorandum Cost Recovery Account [Roll Forward]
Beginning Balance	5,899	5,912	4,328	9,617
Regulatory Asset Increase (Decrease)	1,222	1,049	2,827	(754)
Refunds (Collections) Adjustments	1	(1,871)	(33)	(3,773)
Ending Balance	7,122	5,090	7,122	5,090
Pension
Balancing and Memorandum Cost Recovery Account [Roll Forward]
Beginning Balance	2,985	(233)	2,449	(1,843)
Regulatory Asset Increase (Decrease)	(253)	199	261	582
Refunds (Collections) Adjustments	0	1,208	22	2,435
Ending Balance	2,732	1,174	2,732	1,174
PRVMA
Balancing and Memorandum Cost Recovery Account [Roll Forward]
Beginning Balance	0	0	0	0
Regulatory Asset Increase (Decrease)	1,219	0	1,219	0
Refunds (Collections) Adjustments	(8)	0	(8)	0
Ending Balance	$ 1,211	$ 0	$ 1,211	$ 0

Regulatory Assets and Liabili_3

Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Regulatory Assets [Line Items]
Net Regulatory Assets	$ 136,974	$ 120,417
Less: current regulatory asset, net	4,758	6,472
Total regulatory assets, net, less current portion	132,216	113,945
Deferred Income Tax Charge [Member]
Regulatory Assets [Line Items]
Regulatory assets:	3,363	2,433
Postretirement pensions and other medical benefits
Regulatory Assets [Line Items]
Regulatory assets:	77,906	73,525
Business combinations debt premium, net [Member]
Regulatory Assets [Line Items]
Regulatory assets:	23,114	25,020
Balancing and memorandum accounts, net
Regulatory Assets [Line Items]
Regulatory assets:	21,335	5,283
WRA [Member]
Regulatory Assets [Line Items]
Regulatory assets:	4,805	9,108
Other, net
Regulatory Assets [Line Items]
Regulatory assets:	$ 6,451	$ 5,048

Business Combination (Details)

Business Combination (Details) - USD ($) $ / shares in Units, $ in Thousands	Oct. 09, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Long-term borrowings		$ 85,000	$ 80,000
Borrowings on line of credit		226,884	$ 73,000
Assets Acquired
Goodwill		627,036		$ 627,036	$ 628,287
CTWS [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred, Acquiree's Common Shares Converted In Cash Per Share	$ 70
Payments to Acquire Businesses, Gross	$ 838,476
Cash Acquired from Acquisition	3,011
Adjustments to Additional Paid in Capital, Share-based Compensation, Equity Award Assumed in Acquisition	6,384
Assets Acquired
Utility plant, net	750,703	750,703		750,703
Utility plant, net, measurement period adjustments				0
Nonutility plant	848	848		848
Nonutility plant, measurement period adjustments				0
Current assets	42,673	41,506		41,506
Current assets, measurement period adjustments				(1,167)
Investments	12,489	12,489		12,489
Investments, measurement period adjustments				0
Regulatory assets and deferred charges, less current portion	83,132	78,825		78,825
Regulatory assets and deferred charges, less current portion, measurement period adjustments				(4,307)
Other intangible assets	17,181	17,181		17,181
Other intangible assets, measurement period adjustments				0
Other assets	2,592	2,592		2,592
Other assets, measurement period adjustments				0
Goodwill	626,523	625,301		625,301
Goodwill, measurement period adjustments				(1,222)
Total assets acquired	1,536,141	1,529,445		1,529,445
Total assets acquired, measurement period adjustments				(6,696)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Long-term debt	281,009	281,009		281,009
Long-term debt, measurement period adjustments				0
Current liabilities, including maturities of long-term debt	125,772	125,797		125,797
Current liabilities, including maturities of long-term debt				25
Deferred income taxes	107,789	100,644		100,644
Deferred income taxes, measurement period adjustments				(7,145)
Postretirement benefit plans	31,789	31,789		31,789
Postretirement benefit plan, measurement period adjustments				0
Contributions in aid of construction and construction advances	137,327	137,327		137,327
Contributions in aid of construction and construction advancesPostretirement benefit plan, measurement period adjustments				0
Other long-term liabilities	10,607	11,031		11,031
Other long-term liabilities, measurement period adjustments				424
Total liabilities assumed	694,293	687,597		687,597
Total liabilities assumed, measurement period adjustments				(6,696)
Assumed equity	$ 841,848	$ 841,848		841,848
Assumed equity, measurement period adjustments				$ 0