10-K Filing

SOUTHWEST GAS CORP CIK: 92416 FY 2016

Filing Information

Form Type	10-K
Accession Number	`0001193125-17-062419`
Period End Date	20161231
Filing Date	20170228
Fiscal Year	2016
Fiscal Period	FY
XBRL Instance	swx-20161231.xml

Filing Contents

This filing contains the following financial statements:

Balance Sheet 101 Income Statement 138 Cash Flow Statement 128 Stockholders Equity 39 Comprehensive Income 54

Balance Sheet 101 line items

Line Item	Tag	Value	Unit	Period
Common stock, par	`CommonStockParOrStatedValuePerShare`	$1.00	USD	Point-in-time
Common stock, par	`CommonStockParOrStatedValuePerShare`	$1.00	USD	Point-in-time
Common stock, authorized	`CommonStockSharesAuthorized`	60.00M	shares	Point-in-time
Common stock, authorized	`CommonStockSharesAuthorized`	60.00M	shares	Point-in-time
Common stock, issued	`CommonStockSharesIssued`	47.38M	shares	Point-in-time
Gas plant	`PublicUtilitiesPropertyPlantAndEquipmentPlantInService`	$6.19B	USD	Point-in-time
Gas plant	`PublicUtilitiesPropertyPlantAndEquipmentPlantInService`	$5.85B	USD	Point-in-time
Common stock, issued	`CommonStockSharesIssued`	47.48M	shares	Point-in-time
Common stock, outstanding	`CommonStockSharesOutstanding`	47.48M	shares	Point-in-time
Less: accumulated depreciation	`PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation`	$2.08B	USD	Point-in-time
Common stock, outstanding	`CommonStockSharesOutstanding`	47.38M	shares	Point-in-time
Less: accumulated depreciation	`PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation`	$2.17B	USD	Point-in-time
Acquisition adjustments, net	`PublicUtilitiesPropertyPlantAndEquipmentAmountOfAcquisitionAdjustments1`	$196.00K	USD	Point-in-time
Acquisition adjustments, net	`PublicUtilitiesPropertyPlantAndEquipmentAmountOfAcquisitionAdjustments1`	$370.00K	USD	Point-in-time
Construction work in progress	`PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress`	$119.81M	USD	Point-in-time
Construction work in progress	`PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress`	$111.18M	USD	Point-in-time
Net utility plant (Note 2)	`PublicUtilitiesPropertyPlantAndEquipmentNet`	$3.89B	USD	Point-in-time
Net utility plant (Note 2)	`PublicUtilitiesPropertyPlantAndEquipmentNet`	$4.13B	USD	Point-in-time
Other property and investments (Note 1)	`OtherPropertyAndInvestments`	$313.53M	USD	Point-in-time
Other property and investments (Note 1)	`OtherPropertyAndInvestments`	$342.34M	USD	Point-in-time
Cash and cash equivalents	`CashAndCashEquivalentsAtCarryingValue`	$41.08M	USD	Point-in-time
Cash and cash equivalents	`CashAndCashEquivalentsAtCarryingValue`	$36.00M	USD	Point-in-time
Cash and cash equivalents	`CashAndCashEquivalentsAtCarryingValue`	$39.57M	USD	Point-in-time
Cash and cash equivalents	`CashAndCashEquivalentsAtCarryingValue`	$28.07M	USD	Point-in-time
Accounts receivable, net of allowances (Note 3)	`AccountsReceivableNetCurrent`	$314.51M	USD	Point-in-time
Accounts receivable, net of allowances (Note 3)	`AccountsReceivableNetCurrent`	$285.14M	USD	Point-in-time
Accrued utility revenue	`AccruedUtilityRevenue`	$74.70M	USD	Point-in-time
Accrued utility revenue	`AccruedUtilityRevenue`	$76.20M	USD	Point-in-time
Income taxes receivable, net	`IncomeTaxesReceivable`	$4.46M	USD	Point-in-time
Income taxes receivable, net	`IncomeTaxesReceivable`	$34.17M	USD	Point-in-time
Deferred purchased gas costs (Note 4)	`DeferredGasCost`	$2.61M	USD	Point-in-time
Deferred purchased gas costs (Note 4)	`DeferredGasCost`	$3.59M	USD	Point-in-time
Prepaids and other current assets (Notes 1, 4, and 13)	`PrepaidExpenseAndOtherAssetsCurrent`	$136.83M	USD	Point-in-time
Prepaids and other current assets (Notes 1, 4, and 13)	`PrepaidExpenseAndOtherAssetsCurrent`	$95.20M	USD	Point-in-time
Total current assets	`AssetsCurrent`	$558.17M	USD	Point-in-time
Total current assets	`AssetsCurrent`	$533.31M	USD	Point-in-time
Goodwill (Note 1)	`Goodwill`	$139.98M	USD	Point-in-time
Goodwill (Note 1)	`Goodwill`	$126.14M	USD	Point-in-time
Deferred income taxes (Note 12)	`DeferredTaxAssetsNetNoncurrent`	$1.29M	USD	Point-in-time
Deferred income taxes (Note 12)	`DeferredTaxAssetsNetNoncurrent`	$428.00K	USD	Point-in-time
Deferred charges and other assets (Notes 2, 4, and 13)	`OtherAssetsNoncurrent`	$469.32M	USD	Point-in-time
Deferred charges and other assets (Notes 2, 4, and 13)	`OtherAssetsNoncurrent`	$432.23M	USD	Point-in-time
Total noncurrent assets	`AssetsNoncurrent`	$573.50M	USD	Point-in-time
Total noncurrent assets	`AssetsNoncurrent`	$595.89M	USD	Point-in-time
Total assets	`Assets`	$5.36B	USD	Point-in-time
Total assets	`Assets`	$5.58B	USD	Point-in-time
Total assets	`Assets`	$5.21B	USD	Point-in-time
Common stock, $1 par (authorized - 60,000,000 shares; issued and outstanding - 47,482,068 and 47,377,575 shares) (Note 11)	`CommonStockValue`	$49.11M	USD	Point-in-time
Common stock, $1 par (authorized - 60,000,000 shares; issued and outstanding - 47,482,068 and 47,377,575 shares) (Note 11)	`CommonStockValue`	$49.01M	USD	Point-in-time
Additional paid-in capital	`AdditionalPaidInCapitalCommonStock`	$896.45M	USD	Point-in-time
Additional paid-in capital	`AdditionalPaidInCapitalCommonStock`	$903.12M	USD	Point-in-time
Accumulated other comprehensive income (loss), net (Note 5)	`AccumulatedOtherComprehensiveIncomeLossNetOfTax`	$-50.27M	USD	Point-in-time
Accumulated other comprehensive income (loss), net (Note 5)	`AccumulatedOtherComprehensiveIncomeLossNetOfTax`	$-48.01M	USD	Point-in-time
Retained earnings	`RetainedEarningsAccumulatedDeficit`	$699.22M	USD	Point-in-time
Retained earnings	`RetainedEarningsAccumulatedDeficit`	$759.26M	USD	Point-in-time
Total Southwest Gas Corporation equity	`StockholdersEquity`	$1.59B	USD	Point-in-time
Total Southwest Gas Corporation equity	`StockholdersEquity`	$1.66B	USD	Point-in-time
Noncontrolling interest	`MinorityInterest`	$-2.22M	USD	Point-in-time
Noncontrolling interest	`MinorityInterest`	$-2.08M	USD	Point-in-time
Total equity	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.66B	USD	Point-in-time
Total equity	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.49B	USD	Point-in-time
Total equity	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.41B	USD	Point-in-time
Total equity	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.59B	USD	Point-in-time
Redeemable noncontrolling interest (Note 16)	`RedeemableNoncontrollingInterestEquityCarryingAmount`	$22.59M	USD	Point-in-time
Redeemable noncontrolling interest (Note 16)	`RedeemableNoncontrollingInterestEquityCarryingAmount`	$16.11M	USD	Point-in-time
Long-term debt, less current maturities (Note 7)	`LongTermDebtNoncurrent`	$1.55B	USD	Point-in-time
Long-term debt, less current maturities (Note 7)	`LongTermDebtNoncurrent`	$1.55B	USD	Point-in-time
Total capitalization	`CapitalizationLongtermDebtAndEquity`	$3.23B	USD	Point-in-time
Total capitalization	`CapitalizationLongtermDebtAndEquity`	$3.16B	USD	Point-in-time
Commitments and contingencies (Note 9)	`CommitmentsAndContingencies`	-	USD	Point-in-time
Commitments and contingencies (Note 9)	`CommitmentsAndContingencies`	-	USD	Point-in-time
Current maturities of long-term debt (Note 7)	`LongTermDebtCurrent`	$50.10M	USD	Point-in-time
Current maturities of long-term debt (Note 7)	`LongTermDebtCurrent`	$19.48M	USD	Point-in-time
Short-term debt (Note 8)	`ShortTermBorrowings`	$18.00M	USD	Point-in-time
Short-term debt (Note 8)	`ShortTermBorrowings`	-	USD	Point-in-time
Accounts payable	`AccountsPayableCurrent`	$184.67M	USD	Point-in-time
Accounts payable	`AccountsPayableCurrent`	$164.86M	USD	Point-in-time
Customer deposits	`CustomerDepositsCurrent`	$72.30M	USD	Point-in-time
Customer deposits	`CustomerDepositsCurrent`	$72.63M	USD	Point-in-time
Income taxes payable, net	`IncomeTaxesPayableNet`	$940.00K	USD	Point-in-time
Income taxes payable, net	`IncomeTaxesPayableNet`	$1.91M	USD	Point-in-time
Accrued general taxes	`AccrualForTaxesOtherThanIncomeTaxesCurrent`	$47.34M	USD	Point-in-time
Accrued general taxes	`AccrualForTaxesOtherThanIncomeTaxesCurrent`	$42.92M	USD	Point-in-time
Accrued interest	`InterestPayableCurrent`	$16.17M	USD	Point-in-time
Accrued interest	`InterestPayableCurrent`	$17.94M	USD	Point-in-time
Deferred purchased gas costs (Note 4)	`DeferredGasPurchasesCurrent`	$45.60M	USD	Point-in-time
Deferred purchased gas costs (Note 4)	`DeferredGasPurchasesCurrent`	$90.48M	USD	Point-in-time
Other current liabilities (Notes 2, 4, and 13)	`OtherLiabilitiesCurrent`	$150.03M	USD	Point-in-time
Other current liabilities (Notes 2, 4, and 13)	`OtherLiabilitiesCurrent`	$168.06M	USD	Point-in-time
Total current liabilities	`LiabilitiesCurrent`	$535.04M	USD	Point-in-time
Total current liabilities	`LiabilitiesCurrent`	$628.38M	USD	Point-in-time
Deferred income taxes and investment tax credits, net (Note 12)	`DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits`	$840.65M	USD	Point-in-time
Deferred income taxes and investment tax credits, net (Note 12)	`DeferredIncomeTaxesAndUnamortizedInvestmentTaxCredits`	$769.45M	USD	Point-in-time
Accumulated removal costs (Note 4)	`OtherAccruedLiabilitiesNoncurrent`	$308.00M	USD	Point-in-time
Accumulated removal costs (Note 4)	`OtherAccruedLiabilitiesNoncurrent`	$303.00M	USD	Point-in-time
Other deferred credits and other long-term liabilities (Notes 2, 4, 10, and 13)	`DeferredCreditsAndOtherLiabilitiesNoncurrent`	$570.25M	USD	Point-in-time
Other deferred credits and other long-term liabilities (Notes 2, 4, 10, and 13)	`DeferredCreditsAndOtherLiabilitiesNoncurrent`	$591.56M	USD	Point-in-time
Total deferred income taxes and other credits	`OtherLiabilitiesNoncurrent`	$1.72B	USD	Point-in-time
Total deferred income taxes and other credits	`OtherLiabilitiesNoncurrent`	$1.66B	USD	Point-in-time
Total capitalization and liabilities	`LiabilitiesAndStockholdersEquity`	$5.58B	USD	Point-in-time
Total capitalization and liabilities	`LiabilitiesAndStockholdersEquity`	$5.36B	USD	Point-in-time

Income Statement 138 line items

Line Item	Tag	Value	Unit	Period
Gas operating revenues	`RegulatedOperatingRevenueGas`	$1.45B	USD	Annual
Gas operating revenues	`RegulatedOperatingRevenueGas`	$1.32B	USD	Annual
Gas operating revenues	`RegulatedOperatingRevenueGas`	$1.38B	USD	Annual
Construction revenues	`ConstructionRevenue`	$1.14B	USD	Annual
Construction revenues	`ConstructionRevenue`	$1.01B	USD	Annual
Construction revenues	`ConstructionRevenue`	$739.62M	USD	Annual
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$731.25M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$685.40M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$2.46B	USD	Annual
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$734.22M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$2.46B	USD	Annual
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$547.75M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$538.60M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$641.52M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$627.68M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$608.40M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$505.40M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$539.97M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$2.12B	USD	Annual
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$453.15M	USD	1 Quarter
Total operating revenues	`RegulatedAndUnregulatedOperatingRevenue`	$432.48M	USD	1 Quarter
Net cost of gas sold	`UtilitiesOperatingExpenseGasAndPetroleumPurchased`	$505.36M	USD	Annual
Net cost of gas sold	`UtilitiesOperatingExpenseGasAndPetroleumPurchased`	$563.81M	USD	Annual
Net cost of gas sold	`UtilitiesOperatingExpenseGasAndPetroleumPurchased`	$397.12M	USD	Annual
Operations and maintenance	`UtilitiesOperatingExpenseMaintenanceAndOperations`	$393.20M	USD	Annual
Operations and maintenance	`UtilitiesOperatingExpenseMaintenanceAndOperations`	$401.72M	USD	Annual
Operations and maintenance	`UtilitiesOperatingExpenseMaintenanceAndOperations`	$383.73M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$270.11M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$289.13M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$253.03M	USD	Annual
Taxes other than income taxes	`TaxesExcludingIncomeAndExciseTaxes`	$47.25M	USD	Annual
Taxes other than income taxes	`TaxesExcludingIncomeAndExciseTaxes`	$52.38M	USD	Annual
Taxes other than income taxes	`TaxesExcludingIncomeAndExciseTaxes`	$49.39M	USD	Annual
Construction expenses	`ConstructionAndDevelopmentCosts`	$1.02B	USD	Annual
Construction expenses	`ConstructionAndDevelopmentCosts`	$898.78M	USD	Annual
Construction expenses	`ConstructionAndDevelopmentCosts`	$647.86M	USD	Annual
Total operating expenses	`CostsAndExpenses`	$2.16B	USD	Annual
Total operating expenses	`CostsAndExpenses`	$1.84B	USD	Annual
Total operating expenses	`CostsAndExpenses`	$2.18B	USD	Annual
Operating income	`OperatingIncomeLoss`	$129.56M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$16.14M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$127.06M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$288.33M	USD	Annual
Operating income	`OperatingIncomeLoss`	$295.71M	USD	Annual
Operating income	`OperatingIncomeLoss`	$18.29M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$26.75M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$25.05M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$28.12M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$117.96M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$112.37M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$15.54M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$117.59M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$134.10M	USD	1 Quarter
Operating income	`OperatingIncomeLoss`	$284.48M	USD	Annual
Net interest deductions (Notes 7 and 8)	`InterestExpense`	$72.07M	USD	Annual
Net interest deductions (Notes 7 and 8)	`InterestExpense`	$73.66M	USD	Annual
Net interest deductions (Notes 7 and 8)	`InterestExpense`	$71.88M	USD	Annual
Other income (deductions)	`OtherNonoperatingIncomeExpense`	$9.47M	USD	Annual
Other income (deductions)	`OtherNonoperatingIncomeExpense`	$7.11M	USD	Annual
Other income (deductions)	`OtherNonoperatingIncomeExpense`	$2.88M	USD	Annual
Total other income and (expenses)	`NonoperatingIncomeExpense`	$-64.96M	USD	Annual
Total other income and (expenses)	`NonoperatingIncomeExpense`	$-64.19M	USD	Annual
Total other income and (expenses)	`NonoperatingIncomeExpense`	$-69.00M	USD	Annual
Income before income taxes	`IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest`	$219.52M	USD	Annual
Income before income taxes	`IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest`	$231.52M	USD	Annual
Income before income taxes	`IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest`	$219.33M	USD	Annual
Income tax expense (Note 12)	`IncomeTaxExpenseBenefit`	$79.90M	USD	Annual
Income tax expense (Note 12)	`IncomeTaxExpenseBenefit`	$78.47M	USD	Annual
Income tax expense (Note 12)	`IncomeTaxExpenseBenefit`	$78.37M	USD	Annual
Net income	`ProfitLoss`	$66.70M	USD	1 Quarter
Net income	`ProfitLoss`	$139.43M	USD	Annual
Net income	`ProfitLoss`	$5.06M	USD	1 Quarter
Net income	`ProfitLoss`	$141.15M	USD	Annual
Net income	`ProfitLoss`	$65.69M	USD	1 Quarter
Net income	`ProfitLoss`	$9.63M	USD	1 Quarter
Net income	`ProfitLoss`	$-4.21M	USD	1 Quarter
Net income	`ProfitLoss`	$70.70M	USD	1 Quarter
Net income	`ProfitLoss`	$2.91M	USD	1 Quarter
Net income	`ProfitLoss`	$71.88M	USD	1 Quarter
Net income	`ProfitLoss`	$153.06M	USD	Annual
Net income	`ProfitLoss`	$9.10M	USD	1 Quarter
Net income	`ProfitLoss`	$58.90M	USD	1 Quarter
Net income	`ProfitLoss`	$1.93M	USD	1 Quarter
Net income	`ProfitLoss`	$75.36M	USD	1 Quarter
Net income (loss) attributable to noncontrolling interests	`NetIncomeLossAttributableToNoncontrollingInterest`	$22.00K	USD	Annual
Net income (loss) attributable to noncontrolling interests	`NetIncomeLossAttributableToNoncontrollingInterest`	$1.11M	USD	Annual
Net income (loss) attributable to noncontrolling interests	`NetIncomeLossAttributableToNoncontrollingInterest`	$1.01M	USD	Annual
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$58.75M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$70.78M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$66.12M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$75.45M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$4.95M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$71.98M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$1.97M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$8.94M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$152.04M	USD	Annual
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$-4.73M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$2.47M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$65.18M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$9.63M	USD	1 Quarter
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$141.13M	USD	Annual
Net income attributable to Southwest Gas Corporation	`NetIncomeLoss`	$138.32M	USD	Annual
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$0.11	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.59	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$-0.10	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$0.19	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$3.04	USD	Annual
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$2.94	USD	Annual
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$0.05	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.26	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$0.21	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.54	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$0.04	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.37	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.40	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$1.52	USD	1 Quarter
Basic earnings per share (Notes 1 and 15)	`EarningsPerShareBasic`	$3.20	USD	Annual
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$3.01	USD	Annual
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.51	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$3.18	USD	Annual
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$0.05	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$0.04	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.58	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$-0.10	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.36	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$0.21	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.53	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$0.19	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$2.92	USD	Annual
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.38	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$0.10	USD	1 Quarter
Diluted earnings per share (Notes 1 and 15)	`EarningsPerShareDiluted`	$1.25	USD	1 Quarter
Average number of common shares outstanding	`WeightedAverageNumberOfSharesOutstandingBasic`	47.47M	shares	Annual
Average number of common shares outstanding	`WeightedAverageNumberOfSharesOutstandingBasic`	46.99M	shares	Annual
Average number of common shares outstanding	`WeightedAverageNumberOfSharesOutstandingBasic`	46.49M	shares	Annual
Average shares outstanding (assuming dilution)	`WeightedAverageNumberOfDilutedSharesOutstanding`	46.94M	shares	Annual
Average shares outstanding (assuming dilution)	`WeightedAverageNumberOfDilutedSharesOutstanding`	47.81M	shares	Annual
Average shares outstanding (assuming dilution)	`WeightedAverageNumberOfDilutedSharesOutstanding`	47.38M	shares	Annual

Cash Flow Statement 128 line items

Line Item	Tag	Value	Unit	Period
Net Income	`ProfitLoss`	$1.93M	USD	1 Quarter
Net Income	`ProfitLoss`	$58.90M	USD	1 Quarter
Net Income	`ProfitLoss`	$9.10M	USD	1 Quarter
Net Income	`ProfitLoss`	$153.06M	USD	Annual
Net Income	`ProfitLoss`	$71.88M	USD	1 Quarter
Net Income	`ProfitLoss`	$2.91M	USD	1 Quarter
Net Income	`ProfitLoss`	$75.36M	USD	1 Quarter
Net Income	`ProfitLoss`	$-4.21M	USD	1 Quarter
Net Income	`ProfitLoss`	$9.63M	USD	1 Quarter
Net Income	`ProfitLoss`	$70.70M	USD	1 Quarter
Net Income	`ProfitLoss`	$65.69M	USD	1 Quarter
Net Income	`ProfitLoss`	$66.70M	USD	1 Quarter
Net Income	`ProfitLoss`	$141.15M	USD	Annual
Net Income	`ProfitLoss`	$5.06M	USD	1 Quarter
Net Income	`ProfitLoss`	$139.43M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$253.03M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$270.11M	USD	Annual
Depreciation and amortization	`DepreciationAndAmortization`	$289.13M	USD	Annual
Deferred income taxes	`IncreaseDecreaseInDeferredIncomeTaxes`	$-68.73M	USD	Annual
Deferred income taxes	`IncreaseDecreaseInDeferredIncomeTaxes`	$-48.78M	USD	Annual
Deferred income taxes	`IncreaseDecreaseInDeferredIncomeTaxes`	$-64.31M	USD	Annual
Accounts receivable, net of allowances	`IncreaseDecreaseInAccountsReceivable`	$3.68M	USD	Annual
Accounts receivable, net of allowances	`IncreaseDecreaseInAccountsReceivable`	$39.85M	USD	Annual
Accounts receivable, net of allowances	`IncreaseDecreaseInAccountsReceivable`	$-30.10M	USD	Annual
Accrued utility revenue	`IncreaseDecreaseInUnbilledReceivables`	$800.00K	USD	Annual
Accrued utility revenue	`IncreaseDecreaseInUnbilledReceivables`	$1.20M	USD	Annual
Accrued utility revenue	`IncreaseDecreaseInUnbilledReceivables`	$1.50M	USD	Annual
Deferred purchased gas costs	`IncreaseDecreaseInDeferredGasCost`	$69.34M	USD	Annual
Deferred purchased gas costs	`IncreaseDecreaseInDeferredGasCost`	$-129.57M	USD	Annual
Deferred purchased gas costs	`IncreaseDecreaseInDeferredGasCost`	$-45.86M	USD	Annual
Accounts payable	`IncreaseDecreaseInAccountsPayable`	$-3.49M	USD	Annual
Accounts payable	`IncreaseDecreaseInAccountsPayable`	$21.70M	USD	Annual
Accounts payable	`IncreaseDecreaseInAccountsPayable`	$-41.50M	USD	Annual
Accrued taxes	`IncreaseDecreaseInAccruedTaxesPayable`	$-13.57M	USD	Annual
Accrued taxes	`IncreaseDecreaseInAccruedTaxesPayable`	$26.34M	USD	Annual
Accrued taxes	`IncreaseDecreaseInAccruedTaxesPayable`	$-8.40M	USD	Annual
Other current assets and liabilities	`IncreaseDecreaseInOtherCurrentAssetsAndLiabilitiesNet`	$-18.30M	USD	Annual
Other current assets and liabilities	`IncreaseDecreaseInOtherCurrentAssetsAndLiabilitiesNet`	$29.55M	USD	Annual
Other current assets and liabilities	`IncreaseDecreaseInOtherCurrentAssetsAndLiabilitiesNet`	$-23.38M	USD	Annual
Gains on sale	`GainLossOnSaleOfPropertyPlantEquipment`	$3.10M	USD	Annual
Gains on sale	`GainLossOnSaleOfPropertyPlantEquipment`	$7.15M	USD	Annual
Gains on sale	`GainLossOnSaleOfPropertyPlantEquipment`	$6.17M	USD	Annual
Changes in undistributed stock compensation	`ShareBasedCompensation`	$2.91M	USD	Annual
Changes in undistributed stock compensation	`ShareBasedCompensation`	$7.97M	USD	Annual
Changes in undistributed stock compensation	`ShareBasedCompensation`	$5.46M	USD	Annual
AFUDC	`IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction`	$2.00M	USD	Annual
AFUDC	`IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction`	$3.01M	USD	Annual
AFUDC	`IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction`	$2.29M	USD	Annual
Changes in other assets and deferred charges	`IncreaseDecreaseInOtherOperatingAssets`	$21.73M	USD	Annual
Changes in other assets and deferred charges	`IncreaseDecreaseInOtherOperatingAssets`	$-16.96M	USD	Annual
Changes in other assets and deferred charges	`IncreaseDecreaseInOtherOperatingAssets`	$14.17M	USD	Annual
Changes in other liabilities and deferred credits	`IncreaseDecreaseInOtherOperatingLiabilities`	$10.86M	USD	Annual
Changes in other liabilities and deferred credits	`IncreaseDecreaseInOtherOperatingLiabilities`	$-18.45M	USD	Annual
Changes in other liabilities and deferred credits	`IncreaseDecreaseInOtherOperatingLiabilities`	$15.78M	USD	Annual
Net cash provided by operating activities	`NetCashProvidedByUsedInOperatingActivitiesContinuingOperations`	$598.39M	USD	Annual
Net cash provided by operating activities	`NetCashProvidedByUsedInOperatingActivitiesContinuingOperations`	$547.15M	USD	Annual
Net cash provided by operating activities	`NetCashProvidedByUsedInOperatingActivitiesContinuingOperations`	$346.42M	USD	Annual
Construction expenditures and property additions	`PaymentsToAcquirePropertyPlantAndEquipment`	$396.90M	USD	Annual
Construction expenditures and property additions	`PaymentsToAcquirePropertyPlantAndEquipment`	$488.00M	USD	Annual
Construction expenditures and property additions	`PaymentsToAcquirePropertyPlantAndEquipment`	$529.53M	USD	Annual
Acquisition of businesses, net of cash acquired	`PaymentsToAcquireBusinessesNetOfCashAcquired`	$9.26M	USD	Annual
Acquisition of businesses, net of cash acquired	`PaymentsToAcquireBusinessesNetOfCashAcquired`	$190.50M	USD	Annual
Acquisition of businesses, net of cash acquired	`PaymentsToAcquireBusinessesNetOfCashAcquired`	$17.00M	USD	Annual
Restricted cash	`IncreaseDecreaseInRestrictedCash`	$-1.23M	USD	Annual
Restricted cash	`IncreaseDecreaseInRestrictedCash`	$-785.00K	USD	Annual
Restricted cash	`IncreaseDecreaseInRestrictedCash`	-	USD	Annual
Changes in customer advances	`IncreaseDecreaseInCustomerAdvances`	$20.36M	USD	Annual
Changes in customer advances	`IncreaseDecreaseInCustomerAdvances`	$18.30M	USD	Annual
Changes in customer advances	`IncreaseDecreaseInCustomerAdvances`	$7.90M	USD	Annual
Miscellaneous inflows	`ProceedsFromMiscellaneousInvestingActivities`	$11.61M	USD	Annual
Miscellaneous inflows	`ProceedsFromMiscellaneousInvestingActivities`	$13.04M	USD	Annual
Miscellaneous inflows	`ProceedsFromMiscellaneousInvestingActivities`	$8.35M	USD	Annual
Miscellaneous outflows	`PaymentsForMiscellaneousInvestingActivities`	-	USD	Annual
Miscellaneous outflows	`PaymentsForMiscellaneousInvestingActivities`	-	USD	Annual
Miscellaneous outflows	`PaymentsForMiscellaneousInvestingActivities`	$1.40M	USD	Annual
Net cash used in investing activities	`NetCashProvidedByUsedInInvestingActivitiesContinuingOperations`	$-555.59M	USD	Annual
Net cash used in investing activities	`NetCashProvidedByUsedInInvestingActivitiesContinuingOperations`	$-469.82M	USD	Annual
Net cash used in investing activities	`NetCashProvidedByUsedInInvestingActivitiesContinuingOperations`	$-525.59M	USD	Annual
Issuance of common stock, net	`ProceedsFromIssuanceOfCommonStock`	$35.40M	USD	Annual
Issuance of common stock, net	`ProceedsFromIssuanceOfCommonStock`	$405.00K	USD	Annual
Issuance of common stock, net	`ProceedsFromIssuanceOfCommonStock`	$472.00K	USD	Annual
Dividends paid	`PaymentsOfDividendsCommonStock`	$66.28M	USD	Annual
Dividends paid	`PaymentsOfDividendsCommonStock`	$74.25M	USD	Annual
Dividends paid	`PaymentsOfDividendsCommonStock`	$83.32M	USD	Annual
Centuri distribution to redeemable noncontrolling interest	`PaymentsOfDividendsMinorityInterest`	$99.00K	USD	Annual
Centuri distribution to redeemable noncontrolling interest	`PaymentsOfDividendsMinorityInterest`	-	USD	Annual
Centuri distribution to redeemable noncontrolling interest	`PaymentsOfDividendsMinorityInterest`	$439.00K	USD	Annual
Issuance of long-term debt, net	`ProceedsFromIssuanceOfLongTermDebt`	$135.82M	USD	Annual
Issuance of long-term debt, net	`ProceedsFromIssuanceOfLongTermDebt`	$423.95M	USD	Annual
Issuance of long-term debt, net	`ProceedsFromIssuanceOfLongTermDebt`	$269.23M	USD	Annual
Retirement of long-term debt	`RepaymentsOfLongTermDebt`	$139.16M	USD	Annual
Retirement of long-term debt	`RepaymentsOfLongTermDebt`	$187.97M	USD	Annual
Retirement of long-term debt	`RepaymentsOfLongTermDebt`	$255.27M	USD	Annual
Change in credit facility and commercial paper	`ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper`	-	USD	Annual
Change in credit facility and commercial paper	`ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper`	$140.00M	USD	Annual
Change in credit facility and commercial paper	`ProceedsFromRepaymentsOfLinesOfCreditAndCommercialPaper`	$-145.00M	USD	Annual
Change in short-term debt	`ProceedsFromRepaymentsOfShortTermDebt`	$-18.00M	USD	Annual
Change in short-term debt	`ProceedsFromRepaymentsOfShortTermDebt`	$5.00M	USD	Annual
Change in short-term debt	`ProceedsFromRepaymentsOfShortTermDebt`	$13.00M	USD	Annual
Principal payments on capital lease obligations	`RepaymentsOfDebtAndCapitalLeaseObligations`	$1.42M	USD	Annual
Principal payments on capital lease obligations	`RepaymentsOfDebtAndCapitalLeaseObligations`	$434.00K	USD	Annual
Principal payments on capital lease obligations	`RepaymentsOfDebtAndCapitalLeaseObligations`	$1.35M	USD	Annual
Other	`ProceedsFromPaymentsForOtherFinancingActivities`	$-1.57M	USD	Annual
Other	`ProceedsFromPaymentsForOtherFinancingActivities`	$-1.26M	USD	Annual
Other	`ProceedsFromPaymentsForOtherFinancingActivities`	$41.00K	USD	Annual
Net cash provided by (used in) financing activities	`NetCashProvidedByUsedInFinancingActivitiesContinuingOperations`	$-79.49M	USD	Annual
Net cash provided by (used in) financing activities	`NetCashProvidedByUsedInFinancingActivitiesContinuingOperations`	$207.51M	USD	Annual
Net cash provided by (used in) financing activities	`NetCashProvidedByUsedInFinancingActivitiesContinuingOperations`	$-80.53M	USD	Annual
Effects of currency translation on cash and cash equivalents	`EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations`	$142.00K	USD	Annual
Effects of currency translation on cash and cash equivalents	`EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations`	$-1.41M	USD	Annual
Effects of currency translation on cash and cash equivalents	`EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations`	$-194.00K	USD	Annual
Change in cash and cash equivalents	`CashAndCashEquivalentsPeriodIncreaseDecrease`	$-3.57M	USD	Annual
Change in cash and cash equivalents	`CashAndCashEquivalentsPeriodIncreaseDecrease`	$-7.93M	USD	Annual
Change in cash and cash equivalents	`CashAndCashEquivalentsPeriodIncreaseDecrease`	$-1.51M	USD	Annual
Cash and cash equivalents at beginning of period	`CashAndCashEquivalentsAtCarryingValue`	$41.08M	USD	Point-in-time
Cash and cash equivalents at beginning of period	`CashAndCashEquivalentsAtCarryingValue`	$36.00M	USD	Point-in-time
Cash and cash equivalents at beginning of period	`CashAndCashEquivalentsAtCarryingValue`	$39.57M	USD	Point-in-time
Cash and cash equivalents at beginning of period	`CashAndCashEquivalentsAtCarryingValue`	$28.07M	USD	Point-in-time
Cash and cash equivalents at end of period	`CashAndCashEquivalentsAtCarryingValue`	$39.57M	USD	Point-in-time
Cash and cash equivalents at end of period	`CashAndCashEquivalentsAtCarryingValue`	$41.08M	USD	Point-in-time
Cash and cash equivalents at end of period	`CashAndCashEquivalentsAtCarryingValue`	$36.00M	USD	Point-in-time
Cash and cash equivalents at end of period	`CashAndCashEquivalentsAtCarryingValue`	$28.07M	USD	Point-in-time
Interest paid, net of amounts capitalized	`InterestPaidNet`	$66.62M	USD	Annual
Interest paid, net of amounts capitalized	`InterestPaidNet`	$65.55M	USD	Annual
Interest paid, net of amounts capitalized	`InterestPaidNet`	$67.44M	USD	Annual
Income taxes paid (received)	`IncomeTaxesPaidNet`	$-19.03M	USD	Annual
Income taxes paid (received)	`IncomeTaxesPaidNet`	$24.25M	USD	Annual
Income taxes paid (received)	`IncomeTaxesPaidNet`	$43.23M	USD	Annual

Stockholders Equity 39 line items

Line Item	Tag	Value	Unit	Period
Dividends declared Common, per share	`CommonStockDividendsPerShareDeclared`	$1.80	USD	Annual
Dividends declared Common, per share	`CommonStockDividendsPerShareDeclared`	$1.46	USD	Annual
Dividends declared Common, per share	`CommonStockDividendsPerShareDeclared`	$1.62	USD	Annual
Shares registered and available for issuance	`CommonStockCapitalSharesReservedForFutureIssuance`	3.80M	shares	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.41B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.59B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.66B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.49B	USD	Point-in-time
Balance, Shares	`CommonStockSharesOutstanding`	47.38M	shares	Point-in-time
Balance, Shares	`CommonStockSharesOutstanding`	47.48M	shares	Point-in-time
Common stock issuances, Value	`StockIssuedDuringPeriodValueNewIssues`	$11.03M	USD	Annual
Common stock issuances, Value	`StockIssuedDuringPeriodValueNewIssues`	$6.78M	USD	Annual
Common stock issuances, Value	`StockIssuedDuringPeriodValueNewIssues`	$40.14M	USD	Annual
Net income (loss)	`NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest`	$141.00M	USD	Annual
Net income (loss)	`NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest`	$151.91M	USD	Annual
Net income (loss)	`NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest`	$138.49M	USD	Annual
Redemption value adjustments (Note 16)	`MinorityInterestChangeInRedemptionValue`	$4.71M	USD	Annual
Redemption value adjustments (Note 16)	`MinorityInterestChangeInRedemptionValue`	$-5.77M	USD	Annual
Redemption value adjustments (Note 16)	`MinorityInterestChangeInRedemptionValue`	$-961.00K	USD	Annual
Foreign currency exchange translation adj.	`OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent`	$-1.89M	USD	Annual
Foreign currency exchange translation adj.	`OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent`	$156.00K	USD	Annual
Foreign currency exchange translation adj.	`OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentBeforeTaxPortionAttributableToParent`	$-637.00K	USD	Annual
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 5 and 10)	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$-29.00K	USD	Annual
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 5 and 10)	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$9.91M	USD	Annual
Net actuarial gain (loss) arising during the period, less amortization of unamortized benefit plan cost, net of tax (Notes 5 and 10)	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$278.00K	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.07M	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.08M	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.07M	USD	Annual
Dividends declared Common	`DividendsCommonStock`	$77.19M	USD	Annual
Dividends declared Common	`DividendsCommonStock`	$68.72M	USD	Annual
Dividends declared Common	`DividendsCommonStock`	$86.23M	USD	Annual
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.41B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.59B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.66B	USD	Point-in-time
Balance	`StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest`	$1.49B	USD	Point-in-time
Balance, Attributable to temporary equity	`RedeemableNoncontrollingInterestEquityCarryingAmount`	$22.59M	USD	Point-in-time
Balance, Attributable to temporary equity	`RedeemableNoncontrollingInterestEquityCarryingAmount`	$16.11M	USD	Point-in-time
Balance, Shares	`CommonStockSharesOutstanding`	47.48M	shares	Point-in-time
Balance, Shares	`CommonStockSharesOutstanding`	47.38M	shares	Point-in-time

Comprehensive Income 54 line items

Line Item	Tag	Value	Unit	Period
Net Income	`ProfitLoss`	$1.93M	USD	1 Quarter
Net Income	`ProfitLoss`	$139.43M	USD	Annual
Net Income	`ProfitLoss`	$5.06M	USD	1 Quarter
Net Income	`ProfitLoss`	$66.70M	USD	1 Quarter
Net Income	`ProfitLoss`	$65.69M	USD	1 Quarter
Net Income	`ProfitLoss`	$70.70M	USD	1 Quarter
Net Income	`ProfitLoss`	$9.63M	USD	1 Quarter
Net Income	`ProfitLoss`	$141.15M	USD	Annual
Net Income	`ProfitLoss`	$75.36M	USD	1 Quarter
Net Income	`ProfitLoss`	$2.91M	USD	1 Quarter
Net Income	`ProfitLoss`	$71.88M	USD	1 Quarter
Net Income	`ProfitLoss`	$153.06M	USD	Annual
Net Income	`ProfitLoss`	$9.10M	USD	1 Quarter
Net Income	`ProfitLoss`	$58.90M	USD	1 Quarter
Net Income	`ProfitLoss`	$-4.21M	USD	1 Quarter
Net actuarial gain (loss)	`OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax`	$-18.92M	USD	Annual
Net actuarial gain (loss)	`OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax`	$-14.12M	USD	Annual
Net actuarial gain (loss)	`OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax`	$-107.66M	USD	Annual
Amortization of prior service cost	`OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax`	$828.00K	USD	Annual
Amortization of prior service cost	`OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax`	$220.00K	USD	Annual
Amortization of prior service cost	`OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax`	$828.00K	USD	Annual
Amortization of net actuarial loss	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax`	$-16.78M	USD	Annual
Amortization of net actuarial loss	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax`	$-21.32M	USD	Annual
Amortization of net actuarial loss	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax`	$-14.67M	USD	Annual
Prior service cost	`OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax`	-	USD	Annual
Prior service cost	`OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax`	-	USD	Annual
Prior service cost	`OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax`	$4.13M	USD	Annual
Regulatory adjustment	`OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax`	$-86.99M	USD	Annual
Regulatory adjustment	`OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax`	$3.46M	USD	Annual
Regulatory adjustment	`OtherComprehensiveIncomeDefinedBenefitPlansRegulatoryAdjustmentNetOfTax`	$3.50M	USD	Annual
Net defined benefit pension plans	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$-29.00K	USD	Annual
Net defined benefit pension plans	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$9.91M	USD	Annual
Net defined benefit pension plans	`OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax`	$278.00K	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.07M	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.08M	USD	Annual
Amounts reclassified into net income (Notes 5 and 13)	`OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIOnDerivativesNetOfTax`	$-2.07M	USD	Annual
Net forward-starting interest rate swaps	`OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax`	$2.07M	USD	Annual
Net forward-starting interest rate swaps	`OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax`	$2.07M	USD	Annual
Net forward-starting interest rate swaps	`OtherComprehensiveIncomeLossDerivativesQualifyingAsHedgesNetOfTax`	$2.08M	USD	Annual
Foreign currency translation adjustments	`OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax`	$161.00K	USD	Annual
Foreign currency translation adjustments	`OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax`	$-1.95M	USD	Annual
Foreign currency translation adjustments	`OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax`	$-659.00K	USD	Annual
Total other comprehensive income (loss), net of tax	`OtherComprehensiveIncomeLossNetOfTax`	$-8.50M	USD	Annual
Total other comprehensive income (loss), net of tax	`OtherComprehensiveIncomeLossNetOfTax`	$-159.00K	USD	Annual
Total other comprehensive income (loss), net of tax	`OtherComprehensiveIncomeLossNetOfTax`	$2.27M	USD	Annual
Comprehensive income	`ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest`	$155.32M	USD	Annual
Comprehensive income	`ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest`	$139.27M	USD	Annual
Comprehensive income	`ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest`	$132.65M	USD	Annual
Comprehensive income (loss) attributable to noncontrolling interests	`ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest`	$1.02M	USD	Annual
Comprehensive income (loss) attributable to noncontrolling interests	`ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest`	-	USD	Annual
Comprehensive income (loss) attributable to noncontrolling interests	`ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest`	$1.05M	USD	Annual
Comprehensive income attributable to Southwest Gas Corporation	`ComprehensiveIncomeNetOfTax`	$132.65M	USD	Annual
Comprehensive income attributable to Southwest Gas Corporation	`ComprehensiveIncomeNetOfTax`	$154.30M	USD	Annual
Comprehensive income attributable to Southwest Gas Corporation	`ComprehensiveIncomeNetOfTax`	$138.22M	USD	Annual

Data is extracted from SEC EDGAR XBRL filings. Values shown are as reported in the filing.