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Subsidiary or Equity Method Investee, Sale of Stock, Type [Table] Subsidiary or Equity Method Investee, Sale of Stock, Type [Table] Reduction in authorized return of equity Balancing Accounts, Increase (Decrease) In Authorized Return On Equity, Percentage Balancing Accounts, Increase (Decrease) In Authorized Return On Equity, Percentage New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Earnings per Share Earnings Per Share, Policy [Policy Text Block] Litigation Case [Axis] Litigation Case [Axis] Accrued payables for additions to utility plant Capital Expenditures Incurred but Not yet Paid Segment Reporting Segment Reporting [Table Text Block] Employer plan contributions Defined Contribution Plan, Employer Discretionary Contribution Amount Rate of compensation increase Defined Benefit Plan, Rate Of Compensation Increase Defined Benefit Plan, Rate Of Compensation Increase Repayments of lines of credit Repayments of Lines of Credit Less: Segment Reporting, 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Unallocated Corporate Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Income Statement [Abstract] Income Statement [Abstract] Employee stock purchase plan (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans Document Transition Report Document Transition Report Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Buildings and improvements Investment Building and Building Improvements City Area Code City Area Code Accumulated Other Comprehensive Income AOCI Attributable to Parent 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Litigation Case [Domain] Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Net nonutility properties Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Lines of credit Line of Credit, Current Interest cost Defined Benefit Plan, Interest Cost Regulatory Assets [Line Items] Regulatory Asset [Line Items] Quadvest Wholesale Asset Purchase Agreement Quadvest Wholesale Asset Purchase Agreement [Member] Quadvest Wholesale Asset Purchase Agreement Receipts of advances and contributions in aid of construction Receipts Of Advances And 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Cost of removal Cost of Removal [Member] Cost of Removal Segment Reporting [Table] Segment Reporting [Table] Remaining shares available for issuance (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant At The Market Offering At The Market Offering [Member] At The Market Offering Title of Individual [Axis] Title and Position [Axis] Sale of Stock [Axis] Sale of Stock [Axis] Other current assets Other Assets, Current Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Other (expense) income: Other Nonoperating Income (Expense) [Abstract] All Trading Arrangements All Trading Arrangements [Member] Shares issuable under the plan upon exercise of outstanding awards (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issuable Upon Vesting Share-based Compensation Arrangement by Share-based Payment Award, Shares Issuable Upon Vesting Other 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Asset Purchase Agreement Quadvest Retail Asset Purchase Agreement [Member] Quadvest Retail Asset Purchase Agreement Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Acquisitions Business Combination [Text Block] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Service cost Defined Benefit Plan, Service Cost Issuance of restricted and deferred stock units Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Regulatory assets: Net Regulatory Assets [Abstract] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Cost to retire utility plant, net of salvage Payments for (Proceeds from) Removal Costs Equity Components [Axis] Equity Components [Axis] Income taxes Income Tax Paid, after Refund Received Contributions in aid of construction Contributions in Aid of Construction Capitalization: Capitalization, Long-Term Debt and Equity [Abstract] Entity Interactive Data Current Entity Interactive Data Current Deferred income taxes Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Total utility plant Public Utilities, Property, Plant and Equipment, Plant in Service Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Termination Date Trading Arrangement Termination Date Other 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[Text Block] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Number of shares vested but not issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Vested, Number Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Vested, Number Service-based restricted stock vesting period Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Capitalization and liabilities Liabilities and Equity [Abstract] Award Type [Domain] Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Cash paid (refunded) during the period for: Supplemental Cash Flow Information [Abstract] Per- and Polyfluoroalkyl substances (“PFAS”) legal 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Land Land Employee Stock Purchase Plan Employee Stock Purchase Plan [Member] Employee Stock Purchase Plan [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic (in usd per share) Earnings Per Share, Basic Total current assets Assets, Current Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Long-term debt, less current portion Long-Term Debt, Excluding Current Maturities Award Type [Axis] Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Customers, net of allowances for credit losses of $760 and $722 on June 30, 2026 and December 31, 2025, respectively Accounts Receivable, after Allowance for Credit Loss, Current Retained earnings Retained Earnings (Accumulated Deficit) MWC MWC [Member] MWC Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit 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Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Construction work in progress Public Utilities, Property, Plant and Equipment, Construction Work in Progress Business Segments [Axis] Segments [Axis] Supplemental Employee Retirement Plan Supplemental Employee Retirement Plan [Member] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Plan Name [Axis] Plan Name [Axis] Tabular List, Table Tabular List [Table Text Block] Schedule of Compensation Costs Charged to Income and Proceeds from the ESPP, by Award Type Share-Based Payment Arrangement, Cost by Plan [Table Text Block] Other, net Other Nonoperating Income (Expense) Business combinations debt premium Business Combinations Debt Premium [Member] Business Combinations Debt Premium Income tax Income Taxes Receivable, Current Name Awards Close in Time to MNPI Disclosures, Individual Name Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Administrative and general Administrative and general General and Administrative Expense Sale of stock (in usd per share) Sale of Stock, Price Per Share Water supply costs Water Supply Costs [Member] Water Supply Costs Total regulatory liabilities Regulatory Liability Adjustment to Compensation: Adjustment to Compensation [Axis] 5.91% Senior Note, Series S 5.91% Senior Note, Series S [Member] 5.91% Senior Note, Series S Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Interest, net of amounts capitalized Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Credit Facility [Axis] Credit Facility [Axis] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Regulatory Matters Schedule of Regulatory Assets and Liabilities [Text Block] Other noncurrent assets and noncurrent liabilities Increase (Decrease) in Other Noncurrent Assets and Liabilities Increase (Decrease) in Other Noncurrent Assets and Liabilities Name Measure Name Receivable period for noncurrent cash proceeds receivable form legal settlement Loss Contingency, Receivable, Noncurrent Period Loss Contingency, Receivable, Noncurrent Period Income Taxes Income Tax Disclosure [Text Block] Regulatory liabilities: Net Regulatory Liabilities [Abstract] Net Regulatory Liabilities Accounts payable Accounts Payable, Current Pay vs Performance Disclosure [Line Items] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Asset acquisition, number of appraisers Asset Acquisition, Number Of Appraisers Asset Acquisition, Number Of Appraisers Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Settlement payable to contract operators Settlement Liabilities, Current Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Name Trading Arrangement, Individual Name Schedule of Regulatory Assets, Net Schedule of Regulatory Assets [Table Text Block] Cash and cash equivalents Cash and Cash Equivalent Variable interest entity, ownership percentage Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Company Selected Measure Amount Company Selected Measure Amount Accrued groundwater extraction charges, purchased water and power Accrued Groundwater Extraction Charges, Purchased Water And Power Accrued Groundwater Extraction Charges, Purchased Water And Power Total number of outstanding (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Non-Option Equity Instruments, Outstanding, Number Depreciation and amortization Depreciation, Depletion and Amortization Issuance of restricted and deferred stock units (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Current assets: Assets, Current [Abstract] Non-PEO NEO Non-PEO NEO [Member] Senior Notes Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Total production expenses Production expenses Water Production Costs Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Provision for income taxes Income tax expense Provision (benefit) for income taxes Income Tax Expense (Benefit) Award Timing Method Award Timing Method [Text Block] Net change in cash and cash equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Estimated service lives of assets Public Utilities, Property, Plant and Equipment, Common, Useful Life Proceeds from legal settlements Proceeds from Legal Settlements Net income Net income Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Other Services Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member] Restatement Determination Date: Restatement Determination Date [Axis] Current portion of regulatory liabilities Less: current portion of regulatory liabilities Regulatory Liability, Current 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 Amortization of actuarial gain Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Accounts receivable and accrued unbilled utility revenue Increase (Decrease) in Receivables Alternative revenue programs, net Alternative Revenue Programs, Net Alternative Revenue Programs, Net Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block]