 | us-gaap:WaterProductionCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:CostOfPurchasedWater | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:RecoveryOfDirectCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:ManufacturingCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:DirectOperatingMaintenanceSuppliesCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:OperatingInsuranceAndClaimsCostsProduction | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:FuelCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:DirectCommunicationsAndUtilitiesCostsAbstract | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:AircraftRentalAndLandingFees | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:DirectOperatingCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:WaterProductionCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:CostOfPurchasedWater | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:RecoveryOfDirectCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:ManufacturingCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:DirectOperatingMaintenanceSuppliesCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:OperatingInsuranceAndClaimsCostsProduction | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:FuelCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:DirectCommunicationsAndUtilitiesCostsAbstract | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:AircraftRentalAndLandingFees | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:DirectOperatingCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:WaterProductionCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:CostOfPurchasedWater | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:RecoveryOfDirectCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:ManufacturingCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:DirectOperatingMaintenanceSuppliesCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:OperatingInsuranceAndClaimsCostsProduction | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:FuelCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:DirectCommunicationsAndUtilitiesCostsAbstract | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:AircraftRentalAndLandingFees | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:DirectOperatingCosts | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:WaterProductionCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:CostOfPurchasedWater | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:RecoveryOfDirectCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:ManufacturingCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:DirectOperatingMaintenanceSuppliesCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:OperatingInsuranceAndClaimsCostsProduction | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:FuelCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:DirectCommunicationsAndUtilitiesCostsAbstract | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:AircraftRentalAndLandingFees | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:DirectOperatingCosts | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |