Consolidated Entities [Axis] Consolidated Entities [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Purchased water Cost of Purchased Water Pay vs Performance Disclosure [Line Items] Maintenance Utilities Operating Expense, Maintenance Statistical Measurement [Domain] Statistical Measurement [Domain] Schedule of Regulatory Assets, Net Schedule of Regulatory Assets [Table Text Block] Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Underlying Security Market Price Change Underlying Security Market Price Change, Percent 4.85% Senior Note, Series P 4.85% Senior Note, Series P [Member] 4.85% Senior Note, Series P Award Type [Domain] Award Type [Domain] Fair Value as of Grant Date Award Grant Date Fair Value Income tax temporary differences Future income tax benefits due to customers Deferred Income Tax Charge [Member] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Payments for business acquisition Payments to Acquire Businesses, Gross Employer plan contributions Defined Contribution Plan, Employer Discretionary Contribution Amount Company-funded Payments To Acquire Water Systems Using Company Funds Payments To Acquire Water Systems Using Company Funds Deferred income taxes Deferred Income Tax Liabilities, Net MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Performance Shares Performance Shares [Member] Segment Reporting [Abstract] Segment Reporting [Abstract] Accounts payable Accounts Payable, Current Tax receivable and payable, and other accrued taxes Increase (Decrease) in Accrued Taxes Payable Restatement Determination Date: Restatement Determination Date [Axis] Commitments and contingencies Commitments and Contingencies Insider Trading Policies and Procedures [Line Items] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Water supply costs Water Supply Costs [Member] Water Supply Costs Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Capitalization Equity [Text Block] Issuance of common stock, net of issuance costs Proceeds from Issuance of Common Stock Geographical [Axis] Geographical [Axis] Income Taxes Income Tax Disclosure [Text Block] Stockholders’ equity: Stockholders' Equity, Number of Shares, Par Value and Other Disclosure [Abstract] Revenue Revenue [Policy Text Block] Current liabilities: Liabilities, Current [Abstract] Business Acquisition [Line Items] Business Acquisition [Line Items] Non-tariffed Unregulated Operation [Member] Regulated Regulated Operation [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Dividends paid Payments of Ordinary Dividends, Common Stock Impairment, long-lived asset Impairment, Long-Lived Asset, Held-for-Use Diluted (in usd per share) Earnings Per Share, Diluted Schedule of Investments [Table] Schedule of Investments [Table] PEO Total Compensation Amount PEO Total Compensation Amount Customers, net of allowances for uncollectible accounts of $6,198 and $6,551 on March 31, 2024 and December 31, 2023, respectively Accounts Receivable, after Allowance for Credit Loss, Current Land Land Land Public Utilities, Property, Plant and Equipment, Land Other Other Regulatory Liabilities [Member] Other Regulatory Liabilities Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Current regulatory assets Less: current regulatory assets Regulatory Asset, Current Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Utility plant: Public Utilities, Property, Plant and Equipment, Net [Abstract] Aggregate gross sales price (up to) Sale Of Stock, Aggregate Gross Sales Price Sale Of Stock, Aggregate Gross Sales Price Other (expense) income: Other Nonoperating Income (Expense) [Abstract] Trading Symbol Trading Symbol Non-PEO NEO 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Assets Executive Category: Executive Category [Axis] General Significant Accounting Policies [Text Block] Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Name Measure Name Name Forgone Recovery, Individual Name Other Other Regulatory Assets [Member] Other Regulatory Assets [Member] Goodwill Goodwill Equity Components [Axis] Equity Components [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Remaining shares available for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Asset Acquisition [Domain] Asset Acquisition [Domain] Underlying Securities Award Underlying Securities Amount Entity Small Business Entity Small Business Local Phone Number Local Phone Number Number of subsidiaries Number Of Subsidiaries Number Of Subsidiaries Recovery of Erroneously Awarded Compensation Disclosure [Line Items] At The Market Offering At The Market Offering [Member] At The Market Offering Retirement Plan Type [Domain] Retirement Plan Type [Domain] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Unrecognized pensions and other postretirement benefits Pension and Other Postretirement Plans Costs [Member] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Postretirement benefit plans Liability, Defined Benefit Plan, Noncurrent Schedule of Nonutility Properties and Real Estate Investments Schedule Of Real Estate Investments [Table Text Block] Tabular disclosure of real estate investments. 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activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Award Type [Axis] Award Type [Axis] Anti-dilutive restricted common stock units excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Number of equity instruments granted (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period Plan Name [Domain] Plan Name [Domain] Document Quarterly Report Document Quarterly Report Income tax Income Taxes Receivable, Current Interest on long-term debt and other interest expense Interest Expense Accrued payables for additions to utility plant Capital Expenditures Incurred but Not yet Paid Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Total utility plant Property, Plant and Equipment, Gross Trading Arrangement: Trading Arrangement [Axis] Texas Water Texas Water [Member] Texas Water And TWR PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Entity File Number Entity File Number Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Prepaid expenses Prepaid Expense, Current Employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Entity Shell Company Entity Shell Company Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Restatement Determination Date Restatement Determination Date 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from stock offering Sale of Stock, Consideration Received on Transaction Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Target vesting percentage Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Rights, Percentage Employee Stock Option Employee Stock Option [Member] Recognition period for unrecognized compensation cost Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Other changes, net Proceeds from (Payments for) Other Financing Activities Maximum Maximum [Member] Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Unrecognized compensation costs Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Document Type Document Type Tabular List, Table Tabular List [Table Text Block] Entity Address, Address Line One Entity Address, Address Line One Asset acquisition, period of post-closing production 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Subsequent Event [Member] Other current liabilities Other Liabilities, Current Allowance for equity funds used during construction Public Utilities, Allowance for Funds Used During Construction, Additions Income Statement [Abstract] Income Statement [Abstract] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Common stock issuance, net of costs (in shares) Stock Issued During Period, Shares, New Issues Accrued unbilled utility revenue Receivables, Long-Term Contracts or Programs Operating expense: Costs and Expenses [Abstract] Title of 12(b) Security Title of 12(b) Security Long-Lived Assets Held-for-sale, Name [Domain] Long-Lived Assets Held-for-Sale, Name [Domain] Contributions in aid of construction Contributions in Aid of Construction Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Incentive Plan Incentive Plan [Member] Incentive Plan [Member] Amortization of actuarial loss (gain) Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Revenue adjustment mechanisms Revenue Adjustment Mechanisms [Member] Revenue adjustment mechanisms Customer Assistance Program ("CAP") balancing account Customer Assistance Program Balancing Account [Member] Customer Assistance Program Balancing Account Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Issuance of restricted and deferred stock units Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Other current assets Other Assets, Current Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Unrecognized pensions and other postretirement benefits Unrecognized Pensions and Other Postretirement Benefits [Member] Unrecognized Pensions and Other Postretirement Benefits Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Depreciable plant and equipment Public Utilities, Property, Plant And Equipment, Depreciable Plant And Equipment Public Utilities, Property, Plant And Equipment, Depreciable Plant And Equipment Postretirement benefit plans Assets for Plan Benefits, Defined Benefit Plan Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Entity Tax Identification Number Entity Tax Identification Number Cost of removal Cost of Removal [Member] Cost of Removal Statistical Measurement [Axis] Statistical Measurement [Axis] Entity Interactive Data Current Entity Interactive Data Current Lines of Credit and Long-Term Liabilities Long-Term Debt [Text Block] Other production expenses Utilities Operating Expense, Other Total Shareholder Return Amount Total Shareholder Return Amount Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Supplemental disclosure of non-cash activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Segment [Domain] Segments [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Retained earnings Retained Earnings (Accumulated Deficit) Measure: Measure [Axis] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Name Outstanding Recovery, Individual Name Water Utility Services Reportable Segment One [Member] Reportable Segment One [Member] Aggregate principal amount Debt Instrument, Face Amount Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Current assets: Assets, Current [Abstract] Entity Address, State or Province Entity Address, State or Province Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Schedule 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 Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Common stock, shares outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Dividends paid Dividends Interest cost Defined Benefit Plan, Interest Cost PEO PEO [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Benefit Plans Retirement Benefits [Text Block] Rate of compensation increase Defined Benefit Plan, Rate Of Compensation Increase Defined Benefit Plan, Rate Of Compensation Increase Common stock, par value (in usd per share) Common Stock, Par or Stated Value Per Share Sale of Stock [Axis] Sale of Stock [Axis] Number of service connections from acquisition Public Utilities, Acquisition, Service Connections Public Utilities, Acquisition, Service Connections Class of Stock [Domain] Class of Stock [Domain] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Nonutility properties and real estate investments Nonutility properties and real estate investments Nonutility Properties And Real Estate Investments, At Cost Nonutility Properties And Real Estate Investments, At Cost Estimated employer contributions for the remainder of fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Debt Instrument [Axis] Debt Instrument [Axis] Postretirement benefits Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits Accrued groundwater extraction charges, purchased water and power Increase (Decrease) In Accrued Groundwater Extraction Charges, Purchased Water And Power Increase (Decrease) In Accrued Groundwater Extraction Charges, Purchased Water And Power Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Effective consolidated income tax rate Effective Income Tax Rate Reconciliation, Percent Buildings and improvements Investment Building and Building Improvements Asset Acquisition [Axis] Asset Acquisition [Axis] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Equity Plans Shareholders' Equity and Share-Based Payments [Text Block] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Restricted stock and deferred restricted stock Restricted Stock And Deferred Restricted Stock [Member] Restricted Stock and Deferred Restricted Stock [Member] All Executive Categories All Executive Categories [Member] Advances for construction Contract with Customer, Liability, Noncurrent SJW Group Corporate Segment [Member] Wholesale water supply assets Wholesale Water Supply Assets Wholesale Water Supply Assets Less accumulated depreciation and amortization Nonutility Properties And Real Estate Investments, Accumulated Depreciation And Amortization Nonutility Properties And Real Estate Investments, Accumulated Depreciation And Amortization Title of Individual [Axis] Title of Individual [Axis] Other Nontrade Receivables, Current Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Plan Name [Axis] Plan Name [Axis] Debt Disclosure [Abstract] Earnings per share Earnings Per Share [Abstract] Plan expense Stock or Unit Option Plan Expense Regulatory Asset [Domain] Regulatory Asset [Domain] Common stock, $0.001 par value; authorized 70,000,000 shares; issued and outstanding shares 32,201,216 on March 31, 2024 and 32,023,004 on December 31, 2023 Common Stock, Value, Issued Net utility plant Public Utilities, Property, Plant and Equipment, Net Administrative and general General and Administrative Expense Power Utilities Operating Expense, Purchased Power Weighted average price per share (in usd per share) Sale Of Stock, Weighted Average Price Per Share Sale Of Stock, Weighted Average Price Per Share Weighted-average interest rate on short-term Short-Term Debt, Weighted Average Interest Rate, at Point in Time Capitalization: Capitalization, Long-Term Debt and Equity [Abstract] Net nonutility properties and real estate investments Nonutility Properties And Real Estate Investments, Net Nonutility Properties And Real Estate Investments, Net Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Senior Notes Senior Notes [Member] Total current assets Assets, Current Other intangible asset Other Intangible Assets, Net Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Total Defined Benefit Plan, Net Periodic Benefit Cost (Credit) All Individuals All Individuals [Member] Cash paid during the period for: Supplemental Cash Flow Information [Abstract] Total operating expense Operating expense Utilities Operating Expense Regulatory Assets [Line Items] Regulatory Asset [Line Items] Other, net Other Nonoperating Income (Expense) Entity Filer Category Entity Filer Category Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Cost to retire utility plant, net of salvage Payments for (Proceeds from) Removal Costs Statement [Table] Statement [Table] Current Fiscal Year End Date Current Fiscal Year End Date Earnings per Share Earnings Per Share, Policy [Policy Text Block] Total regulatory liabilities Regulatory Liability Unrecognized tax benefits Unrecognized Tax Benefits PEO Name PEO Name Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Property taxes and other non-income taxes Utilities Operating Expense, Taxes Investments Investments Grant date fair value of equity instruments granted (in usd per share) Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Supplemental Employee Retirement Plan Supplemental Employee Retirement Plan [Member] Regulatory liabilities, less current portion Total regulatory liabilities, less current portion Regulatory Liability, Noncurrent Shares issuable upon exercise of incentive plan awards (in shares) Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Issuable Upon Exercise Number of shares reserved for issuance under equity instrument agreements awarded that validly exist and are outstanding, including vested instruments. 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P. KT Water Resource L. P. [Member] KT Water Resource L. P. 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[Text Block] Other changes, net Payments for (Proceeds from) Other Investing Activities Retained Earnings Retained Earnings [Member] Current portion of long-term debt Long-Term Debt, Current Maturities Utility property installed by developers Utility Property Installed By Developer Utility Property Installed By Developer Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Total capitalization and liabilities Liabilities and Equity Total other assets Other Assets, Noncurrent Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Basic (in usd per share) Earnings Per Share, Basic Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Employee stock purchase plan Stock Issued During Period, Value, Employee Stock Purchase Plan Accounting Policies [Abstract] Accounting Policies [Abstract] Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Depreciation and amortization Depreciation and amortization Utilities Operating Expense, Depreciation and Amortization Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Sale of Stock [Domain] Sale of Stock [Domain] Gain on disposition of assets Gain (Loss) on Disposition of Assets Employee benefit costs Employee Benefit Costs [Member] Employee Benefit Costs Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Fair value of plan assets Defined Benefit Plan, Plan Assets, Amount Southern Comal County, Texas Southern Comal County, Texas [Member] Southern Comal County, Texas Arrangement Duration Trading Arrangement Duration Regulatory Liability [Axis] Regulatory Liability [Axis] Entity Address, City or Town Entity Address, City or Town Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Monterey Water Revenue Adjustment Mechanism Monterey Water Revenue Adjustment Mechanism (MWRAM) [Member] Monterey Water Revenue Adjustment Mechanism (MWRAM) Document Transition Report Document Transition Report Award Timing Predetermined Award Timing Predetermined [Flag] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Termination Date Trading Arrangement Termination Date Accounts payable and other current liabilities Increase (Decrease) in Accounts Payable Common stock, shares authorized (in shares) Common Stock, Shares Authorized Repayments on line of credit Repayments of Lines of Credit Accrued groundwater extraction charges, purchased water and power Accrued Groundwater Extraction Charges, Purchased Water And Power Accrued Groundwater Extraction Charges, Purchased Water And Power Adjustments to reconcile net income to net cash provided by operating activities: 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after Forfeiture All Other Other Segments [Member] Entity Registrant Name Entity Registrant Name Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Award Timing Method Award Timing Method [Text Block] Adjustment to Compensation, Amount Adjustment to Compensation Amount Document Period End Date Document Period End Date Borrowings on line of credit Proceeds from Lines of Credit Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Adoption Date Trading Arrangement Adoption Date Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Other balancing and memorandum accounts and regulatory mechanisms, net Regulatory Balancing And Memorandum Accounts And Regulatory Mechanisms, Net Regulatory Balancing And Memorandum Accounts And Regulatory Mechanisms, Net Repayments of long-term borrowings Repayments of Long-Term Debt Entity Central Index Key Entity Central Index Key Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Compensation costs charged to income: Share-Based Payment Arrangement, Expense Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Intangible assets Finite-Lived Intangible Assets, Gross Provision for income taxes Provision (benefit) for income taxes Income Tax Expense (Benefit) Pension non-service credit (cost) Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component Regulatory assets, net not earning a return Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided Accrued payroll Employee-related Liabilities, Current Acquisitions Business Combination And Asset Acquisitions [Text Block] Business Combination And Asset Acquisitions Name Trading Arrangement, Individual Name Asset acquisition, other current liabilities Asset Acquisition, Current Liabilities, Other Asset Acquisition, Current Liabilities, Other Schedule of SJW Group's Revenue Components Disaggregation of Revenue [Table Text Block] Common stock issuance, net of costs Stock Issued During Period, Value, New Issues Equity [Abstract] Current regulatory liabilities Less: current regulatory liabilities Regulatory Liability, Current Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Regulatory Matters Schedule of Regulatory Assets and Liabilities [Text Block] Amendment Flag Amendment Flag Alternative revenue programs, net Alternative Revenue Programs, Net Alternative Revenue Programs, Net Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Asset acquisition, other intangible asset Asset Acquisition, Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Intangible Asset Asset Acquisition, Recognized Identifiable Assets Acquired And Liabilities Assumed, Other Intangible Asset Regulatory assets and liabilities excluding cost of removal, income tax temporary differences, and postretirement benefits Increase (Decrease) To Regulatory Asset And Liabilities Excluding Cost Of Removal, Income Tax Temporary Differences, Net And Postretirement Benefits Increase (Decrease) To Regulatory Asset And Liabilities Excluding Cost Of Removal, Income Tax Temporary Differences, Net And Postretirement Benefits Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Long-term debt, less current portion Long-Term Debt, Excluding Current Maturities Warehouse Building Warehouse Building [Member] Warehouse Building Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Total production expenses Water Production Costs Regulated Operations [Abstract] Regulated Operations [Abstract] Company Selected Measure Amount Company Selected Measure Amount Additional paid-in capital Additional Paid in Capital, Common Stock Production Expenses: Water Production Costs [Abstract] Water Production Costs [Abstract] Additional Paid-in Capital Additional Paid-in Capital [Member] Weighted average shares outstanding Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Total assets Total assets Assets Name Awards Close in Time to MNPI Disclosures, Individual Name Cover [Abstract] Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Other noncurrent liabilities Other Liabilities, Noncurrent Non-NEOs Non-NEOs [Member] KT Water Development Ltd KT Water Development Ltd [Member] KT Water Development Ltd Asset acquisition, consideration transferred Asset Acquisition, Consideration Transferred Pension Benefits Pension Plan [Member] Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Segment and Non-Tariffed Business Reporting Segment Reporting Disclosure [Text Block] Net change in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Regulated and Unregulated Operation [Domain] Regulated and Unregulated Operation [Domain] Non-PEO NEO Non-PEO NEO [Member] Equity Component [Domain] Equity Component [Domain] Adjustment to Compensation: Adjustment to Compensation [Axis] Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Regulation Status [Axis] Regulation Status [Axis] Authorized revenue, threshold percentage Regulatory Balancing And Memorandum Accounts Review, Authorized Revenue, Threshold Percentage Threshold balance of regulatory balancing or memorandum accounts as a percentage of authorized revenue to trigger an account review. Debt Instrument [Line Items] Debt Instrument [Line Items] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Entity Current Reporting Status Entity Current Reporting Status Operating income Operating income (loss) Operating Income (Loss) Consolidated Entities [Domain] Consolidated Entities [Domain] ESPP proceeds Proceeds, Issuance of Shares, Share-Based Payment Arrangement, Including Option Exercised Rental income Operating Lease, Lease Income Unrealized gain (loss) on investment, tax expense (benefit) Other Comprehensive Income (Loss), Available-for-Sale Securities, Tax, Portion Attributable to Parent Regulatory assets, less current portion Total regulatory assets, less current portion Regulatory Asset, Noncurrent Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Business Segments [Axis] Segments [Axis] Statement [Line Items] Statement [Line Items] Regulatory Asset [Axis] Regulatory Asset [Axis] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Accounts receivable: Accounts Receivable, after Allowance for Credit Loss, Current [Abstract] Estimated service lives of assets Public Utilities, Property, Plant and Equipment, Common, Useful Life