3.26.1 html 171 251 1 false 49 0 false 11 false false R1.htm 0000001 - Document - Cover Sheet http://www.gswater.com/role/Cover Cover Cover 1 false false R2.htm 9952151 - Statement - CONSOLIDATED BALANCE SHEETS Sheet http://www.gswater.com/role/CONSOLIDATEDBALANCESHEETS CONSOLIDATED BALANCE SHEETS Statements 2 false false R3.htm 9952152 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical) Sheet http://www.gswater.com/role/CONSOLIDATEDBALANCESHEETSParenthetical CONSOLIDATED BALANCE SHEETS (Parenthetical) Statements 3 false false R4.htm 9952153 - Statement - CONSOLIDATED STATEMENTS OF INCOME Sheet http://www.gswater.com/role/CONSOLIDATEDSTATEMENTSOFINCOME CONSOLIDATED STATEMENTS OF INCOME Statements 4 false false R5.htm 9952154 - Statement - STATEMENTS OF CHANGES IN COMMON SHAREHOLDER'S EQUITY Sheet http://www.gswater.com/role/STATEMENTSOFCHANGESINCOMMONSHAREHOLDERSEQUITY STATEMENTS OF CHANGES IN COMMON SHAREHOLDER'S EQUITY Statements 5 false false R6.htm 9952155 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOW Sheet http://www.gswater.com/role/CONSOLIDATEDSTATEMENTSOFCASHFLOW CONSOLIDATED STATEMENTS OF CASH FLOW Statements 6 false false R7.htm 9952156 - Disclosure - Summary of Significant Accounting Policies Sheet http://www.gswater.com/role/SummaryofSignificantAccountingPolicies Summary of Significant Accounting Policies Notes 7 false false R8.htm 9952157 - Disclosure - Revenues Sheet http://www.gswater.com/role/Revenues Revenues Notes 8 false false R9.htm 9952158 - Disclosure - Regulatory Matters Sheet http://www.gswater.com/role/RegulatoryMatters Regulatory Matters Notes 9 false false R10.htm 9952159 - Disclosure - Earnings per Share/Capital Stock Sheet http://www.gswater.com/role/EarningsperShareCapitalStock Earnings per Share/Capital Stock Notes 10 false false R11.htm 9952160 - Disclosure - Derivative Instruments Sheet http://www.gswater.com/role/DerivativeInstruments Derivative Instruments Notes 11 false false R12.htm 9952161 - Disclosure - Fair Value of Financial Instruments Sheet http://www.gswater.com/role/FairValueofFinancialInstruments Fair Value of Financial Instruments Notes 12 false false R13.htm 9952162 - Disclosure - Income Taxes Sheet http://www.gswater.com/role/IncomeTaxes Income Taxes Notes 13 false false R14.htm 9952163 - Disclosure - Employee Benefit Plans Sheet http://www.gswater.com/role/EmployeeBenefitPlans Employee Benefit Plans Notes 14 false false R15.htm 9952164 - Disclosure - Contingencies Sheet http://www.gswater.com/role/Contingencies Contingencies Notes 15 false false R16.htm 9952165 - Disclosure - Business Segments Sheet http://www.gswater.com/role/BusinessSegments Business Segments Notes 16 false false R17.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 17 false false R18.htm 9955511 - Disclosure - Summary of Significant Accounting Policies (Policies) Sheet http://www.gswater.com/role/SummaryofSignificantAccountingPoliciesPolicies Summary of Significant Accounting Policies (Policies) Policies http://www.gswater.com/role/SummaryofSignificantAccountingPolicies 18 false false R19.htm 9955512 - Disclosure - Revenues (Tables) Sheet http://www.gswater.com/role/RevenuesTables Revenues (Tables) Tables http://www.gswater.com/role/Revenues 19 false false R20.htm 9955513 - Disclosure - Regulatory Matters (Tables) Sheet http://www.gswater.com/role/RegulatoryMattersTables Regulatory Matters (Tables) Tables http://www.gswater.com/role/RegulatoryMatters 20 false false R21.htm 9955514 - Disclosure - Earnings per Share/Capital Stock (Tables) Sheet http://www.gswater.com/role/EarningsperShareCapitalStockTables Earnings per Share/Capital Stock (Tables) Tables http://www.gswater.com/role/EarningsperShareCapitalStock 21 false false R22.htm 9955515 - Disclosure - Derivative Instruments (Tables) Sheet http://www.gswater.com/role/DerivativeInstrumentsTables Derivative Instruments (Tables) Tables http://www.gswater.com/role/DerivativeInstruments 22 false false R23.htm 9955516 - Disclosure - Fair Value of Financial Instruments: (Tables) Sheet http://www.gswater.com/role/FairValueofFinancialInstrumentsTables Fair Value of Financial Instruments: (Tables) Tables http://www.gswater.com/role/FairValueofFinancialInstruments 23 false false R24.htm 9955517 - Disclosure - Employee Benefit Plans: (Tables) Sheet http://www.gswater.com/role/EmployeeBenefitPlansTables Employee Benefit Plans: (Tables) Tables http://www.gswater.com/role/EmployeeBenefitPlans 24 false false R25.htm 9955518 - Disclosure - Business Segments (Tables) Sheet http://www.gswater.com/role/BusinessSegmentsTables Business Segments (Tables) Tables http://www.gswater.com/role/BusinessSegments 25 false false R26.htm 9955519 - Disclosure - Summary of Significant Accounting Policies (Details) Sheet http://www.gswater.com/role/SummaryofSignificantAccountingPoliciesDetails Summary of Significant Accounting Policies (Details) Details http://www.gswater.com/role/SummaryofSignificantAccountingPoliciesPolicies 26 false false R27.htm 9955520 - Disclosure - Revenues - Narrative (Details) Sheet http://www.gswater.com/role/RevenuesNarrativeDetails Revenues - Narrative (Details) Details 27 false false R28.htm 9955521 - Disclosure - Revenues - Disaggregation of Revenue (Details) Sheet http://www.gswater.com/role/RevenuesDisaggregationofRevenueDetails Revenues - Disaggregation of Revenue (Details) Details 28 false false R29.htm 9955522 - Disclosure - Revenues - Assets and Liabilities (Details) Sheet http://www.gswater.com/role/RevenuesAssetsandLiabilitiesDetails Revenues - Assets and Liabilities (Details) Details 29 false false R30.htm 9955523 - Disclosure - Regulatory Matters - Narrative (Details) Sheet http://www.gswater.com/role/RegulatoryMattersNarrativeDetails Regulatory Matters - Narrative (Details) Details 30 false false R31.htm 9955524 - Disclosure - Regulatory Matters - Schedule of Regulatory Assets (Details) Sheet http://www.gswater.com/role/RegulatoryMattersScheduleofRegulatoryAssetsDetails Regulatory Matters - Schedule of Regulatory Assets (Details) Details 31 false false R32.htm 9955525 - Disclosure - Earnings per Share/Capital Stock - Schedule of EPS (Details) Sheet http://www.gswater.com/role/EarningsperShareCapitalStockScheduleofEPSDetails Earnings per Share/Capital Stock - Schedule of EPS (Details) Details 32 false false R33.htm 9955526 - Disclosure - Earnings per Share/Capital Stock - Narrative (Details) Sheet http://www.gswater.com/role/EarningsperShareCapitalStockNarrativeDetails Earnings per Share/Capital Stock - Narrative (Details) Details 33 false false R34.htm 9955527 - Disclosure - Derivative Instruments - Narrative (Details) Sheet http://www.gswater.com/role/DerivativeInstrumentsNarrativeDetails Derivative Instruments - Narrative (Details) Details 34 false false R35.htm 9955528 - Disclosure - Derivative Instruments - Schedule of Fair Value (Details) Sheet http://www.gswater.com/role/DerivativeInstrumentsScheduleofFairValueDetails Derivative Instruments - Schedule of Fair Value (Details) Details 35 false false R36.htm 9955529 - Disclosure - Fair Value of Financial Instruments - Narrative (Details) Sheet http://www.gswater.com/role/FairValueofFinancialInstrumentsNarrativeDetails Fair Value of Financial Instruments - Narrative (Details) Details 36 false false R37.htm 9955530 - Disclosure - Fair Value of Financial Instruments - Schedule of Outstanding Long-Term Debt (Details) Sheet http://www.gswater.com/role/FairValueofFinancialInstrumentsScheduleofOutstandingLongTermDebtDetails Fair Value of Financial Instruments - Schedule of Outstanding Long-Term Debt (Details) Details 37 false false R38.htm 9955531 - Disclosure - Income Taxes: (Details) Sheet http://www.gswater.com/role/IncomeTaxesDetails Income Taxes: (Details) Details http://www.gswater.com/role/IncomeTaxes 38 false false R39.htm 9955532 - Disclosure - Employee Benefit Plans - Schedule of Net Periodic Costs (Details) Sheet http://www.gswater.com/role/EmployeeBenefitPlansScheduleofNetPeriodicCostsDetails Employee Benefit Plans - Schedule of Net Periodic Costs (Details) Details 39 false false R40.htm 9955533 - Disclosure - Employee Benefit Plans - Narrative (Details) Sheet http://www.gswater.com/role/EmployeeBenefitPlansNarrativeDetails Employee Benefit Plans - Narrative (Details) Details 40 false false R41.htm 9955534 - Disclosure - Contingencies (Details) Sheet http://www.gswater.com/role/ContingenciesDetails Contingencies (Details) Details http://www.gswater.com/role/Contingencies 41 false false R42.htm 9955535 - Disclosure - Business Segments - Narrative (Details) Sheet http://www.gswater.com/role/BusinessSegmentsNarrativeDetails Business Segments - Narrative (Details) Details 42 false false R43.htm 9955536 - Disclosure - Business Segments - Schedule of Business Segments (Details) Sheet http://www.gswater.com/role/BusinessSegmentsScheduleofBusinessSegmentsDetails Business Segments - Schedule of Business Segments (Details) Details 43 false false R44.htm 9955537 - Disclosure - Business Segments - Schedule of PPE and Assets (Details) Sheet http://www.gswater.com/role/BusinessSegmentsScheduleofPPEandAssetsDetails Business Segments - Schedule of PPE and Assets (Details) Details 44 false false All Reports Book All Reports awr-20260331.htm awr-20260331.xsd awr-20260331_cal.xml awr-20260331_def.xml awr-20260331_lab.xml awr-20260331_pre.xml http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 true true