$BKH
BLACK HILLS CORP /SD/ Stock $bkh

$bkh Overview Financials Valuation SEC Filings Company Website

2015 Q4 Form 10-K Financial Statement

#000113046417000010 Filed on February 27, 2017

Income Statement

Concept	2015 Q4	2015 Q3	2015 Q2
Revenue	$318.3M	$272.1M	$272.3M
YoY Change	-15.82%	0.01%	-3.88%
Cost Of Revenue
YoY Change
Gross Profit
YoY Change
Gross Profit Margin
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$9.700M	$37.77M	$40.05M
YoY Change	-73.71%	3.11%	11.63%
% of Gross Profit
Operating Expenses	$246.9M	$274.1M	$311.1M
YoY Change	-19.0%	26.42%	31.92%
Operating Profit	$197.0K	-$2.044M	-$38.86M
YoY Change	-99.72%	-103.7%	-181.96%
Interest Expense	-$23.30M	-$21.20M	-$18.60M
YoY Change	25.95%	26.19%	10.71%
% of Operating Profit	-11827.41%
Other Income/Expense, Net	$600.0K	$842.0K	$395.0K
YoY Change	0.0%	222.61%	-3.42%
Pretax Income	-$21.70M	-$21.98M	-$56.94M
YoY Change	-139.17%	-156.35%	-281.89%
Income Tax	-$7.500M	-$12.04M	-$20.32M
% Of Pretax Income
Net Earnings	-$14.20M	-$9.943M	-$41.84M
YoY Change	-139.34%	-136.29%	-306.12%
Net Earnings / Revenue	-4.46%	-3.65%	-15.37%
Basic Earnings Per Share	-$0.30	-$0.22	-$0.94
Diluted Earnings Per Share	-$0.30	-$0.22	-$0.94
COMMON SHARES
Basic Shares Outstanding	44.85M shares	44.64M shares	44.62M shares
Diluted Shares Outstanding		44.64M shares	44.62M shares

Balance Sheet

Concept	2015 Q4	2015 Q3	2015 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$440.9M	$38.80M	$87.20M
YoY Change	1979.72%	226.05%	493.2%
Cash & Equivalents	$440.9M	$38.84M	$87.21M
Short-Term Investments
Other Short-Term Assets	$71.76M	$55.38M	$51.32M
YoY Change	188.88%	108.98%	136.91%
Inventory	$86.94M	$90.35M	$73.75M
Prepaid Expenses
Receivables	$147.5M	$115.5M	$123.7M
Other Receivables	$400.0K	$0.00	$700.0K
Total Short-Term Assets	$806.5M	$402.3M	$438.6M
YoY Change	77.62%	7.58%	27.47%
LONG-TERM ASSETS
Property, Plant & Equipment	$3.259B	$3.265B	$3.204B
YoY Change	1.67%	4.62%	5.13%
Goodwill	$359.8M	$359.5M	$353.4M
YoY Change	1.8%	1.73%	0.0%
Intangibles	$3.380M	$3.440M	$3.211M
YoY Change	6.42%	6.47%	-2.28%
Long-Term Investments	$12.00M	$12.10M	$12.10M
YoY Change	-30.64%	-29.24%	-29.24%
Other Assets	$7.382M	$7.501M	$17.31M
YoY Change	-74.62%	-74.94%	-45.57%
Total Long-Term Assets	$549.1M	$552.8M	$554.7M
YoY Change	-3.52%	4.9%	5.32%
TOTAL ASSETS
Total Short-Term Assets	$806.5M	$402.3M	$438.6M
Total Long-Term Assets	$549.1M	$552.8M	$554.7M
Total Assets	$4.627B	$4.232B	$4.209B
YoY Change	8.97%	4.79%	6.96%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$89.79M	$91.63M	$78.02M
YoY Change	-27.67%	-8.77%	-22.06%
Accrued Expenses	$232.1M	$229.9M	$160.5M
YoY Change	36.41%	40.71%	13.71%
Deferred Revenue
YoY Change
Short-Term Debt	$76.80M	$117.9M	$105.8M
YoY Change	2.4%	-35.92%	-20.3%
Long-Term Debt Due	$0.00	$0.00	$0.00
YoY Change	-100.0%	-100.0%	-100.0%
Total Short-Term Liabilities	$406.4M	$448.7M	$358.5M
YoY Change	-37.61%	-38.29%	-45.12%
LONG-TERM LIABILITIES
Long-Term Debt	$1.854B	$1.553B	$1.556B
YoY Change	46.24%	40.24%	38.72%
Other Long-Term Liabilities	$155.4M	$136.5M	$154.7M
YoY Change	0.62%	-5.29%	12.26%
Total Long-Term Liabilities	$900.7M	$942.9M	$983.2M
YoY Change	-7.44%	8.47%	16.82%
TOTAL LIABILITIES
Total Short-Term Liabilities	$406.4M	$448.7M	$358.5M
Total Long-Term Liabilities	$900.7M	$942.9M	$983.2M
Total Liabilities	$1.307B	$1.392B	$1.342B
YoY Change	-19.54%	-12.83%	-10.25%
SHAREHOLDERS EQUITY
Retained Earnings	$472.5M	$504.9M	$533.0M
YoY Change	-18.14%	-9.87%	-3.13%
Common Stock	$51.23M	$44.89M	$44.87M
YoY Change	14.58%	-94.33%	-94.31%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$1.888M	$1.789M	$1.771M
YoY Change	0.69%	-2.82%	-1.67%
Treasury Stock Shares	39.72K shares	36.71K shares	35.86K shares
Shareholders Equity	$1.466B	$1.287B	$1.311B
YoY Change
Total Liabilities & Shareholders Equity	$4.627B	$4.232B	$4.209B
YoY Change	8.97%	4.79%	6.96%

Cashflow Statement

Concept	2015 Q4	2015 Q3	2015 Q2
OPERATING ACTIVITIES
Net Income	-$14.20M	-$9.943M	-$41.84M
YoY Change	-139.34%	-136.29%	-306.12%
Depreciation, Depletion And Amortization	$9.700M	$37.77M	$40.05M
YoY Change	-73.71%	3.11%	11.63%
Cash From Operating Activities	$58.50M	$111.5M	$102.9M
YoY Change	-23.13%	70.49%	35.93%
INVESTING ACTIVITIES
Capital Expenditures	$83.10M	-$143.0M	-$89.00M
YoY Change	-176.8%	26.55%	-5.02%
Acquisitions
YoY Change
Other Investing Activities	-$202.8M	-$6.500M	-$400.0K
YoY Change	793.39%	-128.26%	-300.0%
Cash From Investing Activities	-$119.7M	-$149.6M	-$89.20M
YoY Change	-8.49%	66.22%	-4.6%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	475.3M	-10.30M	10.10M
YoY Change	751.79%	-146.82%	-31.76%
NET CHANGE
Cash From Operating Activities	58.50M	111.5M	102.9M
Cash From Investing Activities	-119.7M	-149.6M	-89.20M
Cash From Financing Activities	475.3M	-10.30M	10.10M
Net Change In Cash	414.1M	-48.40M	23.80M
YoY Change	37545.45%	1761.54%	-893.33%
FREE CASH FLOW
Cash From Operating Activities	$58.50M	$111.5M	$102.9M
Capital Expenditures	$83.10M	-$143.0M	-$89.00M
Free Cash Flow	-$24.60M	$254.5M	$191.9M
YoY Change	-113.35%	42.66%	13.28%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2015	bkh	Asset Retirement Obligation Liabilities Acquired AssetRetirementObligationLiabilitiesAcquired	0	USD
CY2016	bkh	Asset Retirement Obligation Liabilities Acquired AssetRetirementObligationLiabilitiesAcquired	22412000	USD
CY2016Q4	bkh	At The Market Equity Offering Program Authorized Aggregate Value AtTheMarketEquityOfferingProgramAuthorizedAggregateValue	200000000	USD
CY2014	bkh	Average Crude Oil Price Per Barrel Nymex AverageCrudeOilPricePerBarrelNYMEX	94.99
CY2015	bkh	Average Crude Oil Price Per Barrel Nymex AverageCrudeOilPricePerBarrelNYMEX	50.28
CY2016	bkh	Average Crude Oil Price Per Barrel Nymex AverageCrudeOilPricePerBarrelNYMEX	42.75
CY2014	bkh	Average Crude Oil Price Per Barrel Wellhead AverageCrudeOilPricePerBarrelWellhead	85.80
CY2015	bkh	Average Crude Oil Price Per Barrel Wellhead AverageCrudeOilPricePerBarrelWellhead	44.72
CY2016	bkh	Average Crude Oil Price Per Barrel Wellhead AverageCrudeOilPricePerBarrelWellhead	37.35
CY2014	bkh	Average Natural Gas Liquids Price Per Mcfnymex AverageNaturalGasLiquidsPricePerMCFNYMEX	0.00
CY2015	bkh	Average Natural Gas Liquids Price Per Mcfnymex AverageNaturalGasLiquidsPricePerMCFNYMEX	0.00
CY2016	bkh	Average Natural Gas Liquids Price Per Mcfnymex AverageNaturalGasLiquidsPricePerMCFNYMEX	0.00
CY2014	bkh	Average Natural Gas Liquids Price Per Mcf Wellhead AverageNaturalGasLiquidsPricePerMCFWellhead	34.81
CY2015	bkh	Average Natural Gas Liquids Price Per Mcf Wellhead AverageNaturalGasLiquidsPricePerMCFWellhead	18.96
CY2016	bkh	Average Natural Gas Liquids Price Per Mcf Wellhead AverageNaturalGasLiquidsPricePerMCFWellhead	11.92
CY2014	bkh	Average Natural Gas Price Per Mcfnymex AverageNaturalGasPricePerMCFNYMEX	4.35
CY2015	bkh	Average Natural Gas Price Per Mcfnymex AverageNaturalGasPricePerMCFNYMEX	2.59
CY2016	bkh	Average Natural Gas Price Per Mcfnymex AverageNaturalGasPricePerMCFNYMEX	2.48
CY2014	bkh	Average Natural Gas Price Per Mcf Wellhead AverageNaturalGasPricePerMCFWellhead	3.33
CY2015	bkh	Average Natural Gas Price Per Mcf Wellhead AverageNaturalGasPricePerMCFWellhead	1.27
CY2016	bkh	Average Natural Gas Price Per Mcf Wellhead AverageNaturalGasPricePerMCFWellhead	2.25
CY2016	bkh	Business Acquisition Pro Forma Combined Federaland Stateincome Tax Rate BusinessAcquisitionProFormaCombinedFederalandStateincomeTaxRate	0.37
CY2015Q2	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	500000	USD
CY2015Q3	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	2800000	USD
CY2015Q4	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	3700000	USD
CY2016Q1	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	15000000	USD
CY2016Q2	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	4100000	USD
CY2016Q3	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	4100000	USD
CY2016Q4	bkh	Business Combination Acquisition Related Costs Net Of Tax BusinessCombinationAcquisitionRelatedCostsNetOfTax	5500000	USD
CY2016Q1	bkh	Business Combination Consideration Transferred Netof Long Term Debtand Cash Acquired BusinessCombinationConsiderationTransferredNetofLongTermDebtandCashAcquired	-1124238000	USD
CY2014	bkh	Business Combination Consideration Transferred Netof Long Term Debtand Cash Acquired BusinessCombinationConsiderationTransferredNetofLongTermDebtandCashAcquired	0	USD
CY2015	bkh	Business Combination Consideration Transferred Netof Long Term Debtand Cash Acquired BusinessCombinationConsiderationTransferredNetofLongTermDebtandCashAcquired	21970000	USD
CY2016	bkh	Business Combination Consideration Transferred Netof Long Term Debtand Cash Acquired BusinessCombinationConsiderationTransferredNetofLongTermDebtandCashAcquired	1124238000	USD
CY2016	bkh	Business Combination Consideration Transferred Netof Long Term Debtand Cash Acquired Before Working Capital Adjustment BusinessCombinationConsiderationTransferredNetofLongTermDebtandCashAcquiredBeforeWorkingCapitalAdjustment	1135000000	USD
CY2016Q1	bkh	Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Working Capital Adjustment To Goodwill BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedWorkingCapitalAdjustmentToGoodwill	6700000	USD
CY2016	bkh	Capital Expenditure For Proved Undeveloped Reserve CapitalExpenditureForProvedUndevelopedReserve	0	USD
CY2014	bkh	Capitalized Interest CapitalizedInterest	982000	USD
CY2015	bkh	Capitalized Interest CapitalizedInterest	1309000	USD
CY2016	bkh	Capitalized Interest CapitalizedInterest	1197000	USD
CY2016	bkh	Capitalized Interest Of Cost Excluded From Amortization CapitalizedInterestOfCostExcludedFromAmortization	890000	USD
CY2015Q4	bkh	Corporate Units Ownership Interest Percentage In Subordinated Notes CorporateUnitsOwnershipInterestPercentageInSubordinatedNotes	0.05
CY2015Q4	bkh	Debt Instrument Convertible Consecutive Trading Daysfor Calculationof Applicable Market Value DebtInstrumentConvertibleConsecutiveTradingDaysforCalculationofApplicableMarketValue	P20D
CY2015Q4	bkh	Debt Instrument Convertible Conversion Ratio Basis Stated Principal Amount DebtInstrumentConvertibleConversionRatioBasisStatedPrincipalAmount	1000	USD
CY2015Q4	bkh	Debt Instrument Convertible If Applicable Market Value Greater Than Reference Price Amount Used To Calculate Numberof Shares Numerator DebtInstrumentConvertibleIfApplicableMarketValueGreaterThanReferencePriceAmountUsedToCalculateNumberofSharesNumerator	50
CY2015Q4	bkh	Debt Instrument Convertible Present Value Of Future Contract Adjustment Payments DebtInstrumentConvertiblePresentValueOfFutureContractAdjustmentPayments	23335000	USD
CY2015Q4	bkh	Debt Instrument Convertible Reference Price DebtInstrumentConvertibleReferencePrice	40.25
CY2015Q4	bkh	Deferred Tax Liability State DeferredTaxLiabilityState	35065000	USD
CY2016Q4	bkh	Deferred Tax Liability State DeferredTaxLiabilityState	47987000	USD
CY2016	bkh	Defined Contribution Plan Employee Vesting Period DefinedContributionPlanEmployeeVestingPeriod	P5Y
CY2016Q2	bkh	Early Termination Settlement Of Gas Supply Contract EarlyTerminationSettlementOfGasSupplyContract	40000000	USD
CY2016Q2	bkh	Early Termination Settlement Of Gas Supply Contract Percentage Of Contract Committed To Distribution Customers EarlyTerminationSettlementOfGasSupplyContractPercentageOfContractCommittedToDistributionCustomers	0.75
CY2016Q2	bkh	Early Termination Settlement Of Gas Supply Contract Percentage Of Contract Not Subjectto Regulatory Recovery EarlyTerminationSettlementOfGasSupplyContractPercentageOfContractNotSubjecttoRegulatoryRecovery	0.25
CY2014	bkh	Effective Income Tax Rate Reconciliation Allowance For Other Funds Used During Construction Equity EffectiveIncomeTaxRateReconciliationAllowanceForOtherFundsUsedDuringConstructionEquity	-0.001
CY2015	bkh	Effective Income Tax Rate Reconciliation Allowance For Other Funds Used During Construction Equity EffectiveIncomeTaxRateReconciliationAllowanceForOtherFundsUsedDuringConstructionEquity	0.003
CY2016	bkh	Effective Income Tax Rate Reconciliation Allowance For Other Funds Used During Construction Equity EffectiveIncomeTaxRateReconciliationAllowanceForOtherFundsUsedDuringConstructionEquity	-0.011
CY2014	bkh	Effective Income Tax Rate Reconciliation Flow Through Accounting EffectiveIncomeTaxRateReconciliationFlowThroughAccounting	-0.009
CY2015	bkh	Effective Income Tax Rate Reconciliation Flow Through Accounting EffectiveIncomeTaxRateReconciliationFlowThroughAccounting	0.038
CY2016	bkh	Effective Income Tax Rate Reconciliation Flow Through Accounting EffectiveIncomeTaxRateReconciliationFlowThroughAccounting	-0.051
CY2014	bkh	Effective Tax Rate Reconciliation Investment Tax Credits And Excess Deferred EffectiveTaxRateReconciliationInvestmentTaxCreditsAndExcessDeferred	0.001
CY2015	bkh	Effective Tax Rate Reconciliation Investment Tax Credits And Excess Deferred EffectiveTaxRateReconciliationInvestmentTaxCreditsAndExcessDeferred	-0.002
CY2016	bkh	Effective Tax Rate Reconciliation Investment Tax Credits And Excess Deferred EffectiveTaxRateReconciliationInvestmentTaxCreditsAndExcessDeferred	0.001
CY2015Q4	bkh	Equity Unit Annual Dividend Amount EquityUnitAnnualDividendAmount	2.125
CY2015Q4	bkh	Equity Unit Dividend Rate Percentage Annual EquityUnitDividendRatePercentageAnnual	0.0425
CY2016	bkh	Estimated Future Development Costsof Proved Undeveloped Wells EstimatedFutureDevelopmentCostsofProvedUndevelopedWells	0	USD
CY2015	bkh	Finite Lived Intangible Asset Purchase Accounting Adjustments FiniteLivedIntangibleAssetPurchaseAccountingAdjustments	434000	USD
CY2014	bkh	Finite Lived Intangible Asset Purchase Accounting Adjustments FiniteLivedIntangibleAssetPurchaseAccountingAdjustments	0	USD
CY2016	bkh	Finite Lived Intangible Asset Purchase Accounting Adjustments FiniteLivedIntangibleAssetPurchaseAccountingAdjustments	5522000	USD
CY2014	bkh	Fuel Purchased Power And Cost Of Gas Sold FuelPurchasedPowerAndCostOfGasSold	581782000	USD
CY2015	bkh	Fuel Purchased Power And Cost Of Gas Sold FuelPurchasedPowerAndCostOfGasSold	456887000	USD
CY2016	bkh	Fuel Purchased Power And Cost Of Gas Sold FuelPurchasedPowerAndCostOfGasSold	499132000	USD
CY2015Q4	bkh	Gross Amounts Offset In Statement Of Financial Position Assets GrossAmountsOffsetInStatementOfFinancialPositionAssets	12937000	USD
CY2016Q4	bkh	Gross Amounts Offset In Statement Of Financial Position Assets GrossAmountsOffsetInStatementOfFinancialPositionAssets	5995000	USD
CY2015Q4	bkh	Gross Amounts Offset In Statement Of Financial Position Liabilities GrossAmountsOffsetInStatementOfFinancialPositionLiabilities	25141000	USD
CY2016Q4	bkh	Gross Amounts Offset In Statement Of Financial Position Liabilities GrossAmountsOffsetInStatementOfFinancialPositionLiabilities	11144000	USD
CY2015Q1	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	14000000	USD
CY2015Q2	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	66000000	USD
CY2015Q3	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	36000000	USD
CY2015Q4	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	44000000	USD
CY2016Q1	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	8800000	USD
CY2016Q2	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	16000000	USD
CY2016Q3	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	7900000	USD
CY2016Q4	bkh	Impairment Of Oil And Gas Properties Net Of Tax ImpairmentOfOilAndGasPropertiesNetOfTax	34000000	USD
CY2014	bkh	Investment Tax Credit Amortization InvestmentTaxCreditAmortization	206000	USD
CY2015	bkh	Investment Tax Credit Amortization InvestmentTaxCreditAmortization	113000	USD
CY2016	bkh	Investment Tax Credit Amortization InvestmentTaxCreditAmortization	52000	USD
CY2015Q4	bkh	Long Term Debt Before The Deduction Of Deferred Financing Costs LongTermDebtBeforeTheDeductionOfDeferredFinancingCosts	1866866000	USD
CY2016Q4	bkh	Long Term Debt Before The Deduction Of Deferred Financing Costs LongTermDebtBeforeTheDeductionOfDeferredFinancingCosts	3238754000	USD
CY2014	bkh	Non Cash Revision To Capitalized Asset Retirement Costs NonCashRevisionToCapitalizedAssetRetirementCosts	-5634000	USD
CY2015	bkh	Non Cash Revision To Capitalized Asset Retirement Costs NonCashRevisionToCapitalizedAssetRetirementCosts	-518000	USD
CY2016	bkh	Non Cash Revision To Capitalized Asset Retirement Costs NonCashRevisionToCapitalizedAssetRetirementCosts	8577000	USD
CY2014	bkh	Operating Expense Maintenance Operationsand Other Costsand Expense OperatingExpenseMaintenanceOperationsandOtherCostsandExpense	359095000	USD
CY2015	bkh	Operating Expense Maintenance Operationsand Other Costsand Expense OperatingExpenseMaintenanceOperationsandOtherCostsandExpense	361109000	USD
CY2016	bkh	Operating Expense Maintenance Operationsand Other Costsand Expense OperatingExpenseMaintenanceOperationsandOtherCostsandExpense	456399000	USD
CY2015Q4	bkh	Premiumon Publicly Traded Equity Units Known As Corporate Units PremiumonPubliclyTradedEquityUnitsKnownAsCorporateUnits	33000000	USD
CY2015	bkh	Premiumon Publicly Traded Equity Units Known As Corporate Units PremiumonPubliclyTradedEquityUnitsKnownAsCorporateUnits	33118000	USD
CY2015Q4	bkh	Proceeds From Issuance Of Common Stockand Sale Of Interest In Corporate Units ProceedsFromIssuanceOfCommonStockandSaleOfInterestInCorporateUnits	536000000	USD
CY2015	bkh	Property Plantand Equipment Including New Asset Acquisitions Gross Period Increase Decrease PropertyPlantandEquipmentIncludingNewAssetAcquisitionsGrossPeriodIncreaseDecrease	480791000	USD
CY2016	bkh	Property Plantand Equipment Including New Asset Acquisitions Gross Period Increase Decrease PropertyPlantandEquipmentIncludingNewAssetAcquisitionsGrossPeriodIncreaseDecrease	1591357000	USD
CY2016Q4	bkh	Proved Undeveloped Reserve Locations ProvedUndevelopedReserveLocations	0	PUD_Location
CY2016	bkh	Proved Undeveloped Reserves ProvedUndevelopedReserves	0	Mcfe
CY2016	bkh	Proved Undeveloped Reserves Extensions Discoveries And Additions ProvedUndevelopedReservesExtensionsDiscoveriesAndAdditions	100000	Mcfe
CY2016	bkh	Proved Undeveloped Reserves Revisions Of Previous Estimates ProvedUndevelopedReservesRevisionsOfPreviousEstimates	-9400000	Mcfe
CY2014	bkh	Public Utilities Allowance For Funds Used During Construction Borrowed Interest Costs Capitalized PublicUtilitiesAllowanceForFundsUsedDuringConstructionBorrowedInterestCostsCapitalized	1075000	USD
CY2015	bkh	Public Utilities Allowance For Funds Used During Construction Borrowed Interest Costs Capitalized PublicUtilitiesAllowanceForFundsUsedDuringConstructionBorrowedInterestCostsCapitalized	1250000	USD
CY2016	bkh	Public Utilities Allowance For Funds Used During Construction Borrowed Interest Costs Capitalized PublicUtilitiesAllowanceForFundsUsedDuringConstructionBorrowedInterestCostsCapitalized	2981000	USD
CY2016Q4	bkh	Pud Developed Pud Location PudDevelopedPudLocation	0	PUD_Location
CY2016	bkh	Reserves Replaced ReservesReplaced	0.00
CY2016	bkh	Securities Excluded From Diluted Earnings Per Share Due To Net Loss SecuritiesExcludedFromDilutedEarningsPerShareDueToNetLoss	83000	shares
CY2014	bkh	Total Other Income Expense TotalOtherIncomeExpense	-66353000	USD
CY2015	bkh	Total Other Income Expense TotalOtherIncomeExpense	-79317000	USD
CY2016	bkh	Total Other Income Expense TotalOtherIncomeExpense	-129480000	USD
CY2016	dei	Amendment Flag AmendmentFlag	false
CY2016	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2016	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2016	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2016
CY2016	dei	Document Period End Date DocumentPeriodEndDate	2016-12-31
CY2016	dei	Document Type DocumentType	10-K
CY2016	dei	Entity Central Index Key EntityCentralIndexKey	0001130464
CY2017Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	53384259	shares
CY2016	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2016	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2016Q2	dei	Entity Public Float EntityPublicFloat	3248873889	USD
CY2016	dei	Entity Registrant Name EntityRegistrantName	BLACK HILLS CORP /SD/
CY2016	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2016	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
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CY2016Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	153477000	USD
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CY2016Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	263289000	USD
CY2015Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	32393000	USD
CY2016Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	40004000	USD
CY2015Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	0	USD
CY2016Q4	us-gaap	Accrued Income Taxes Current AccruedIncomeTaxesCurrent	12552000	USD
CY2015Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	232061000	USD
CY2016Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	244034000	USD
CY2015Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	1717684000	USD
CY2016Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	1943234000	USD
CY2014Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-15044000	USD
CY2015Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-9055000	USD
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-34883000	USD
CY2016	us-gaap	Acquisition Costs AcquisitionCosts	10241000	USD
CY2015Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	953044000	USD
CY2016Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	1138982000	USD
CY2014	us-gaap	Adjustment To Additional Paid In Capital Income Tax Effect From Share Based Compensation Net AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet	-499000	USD
CY2015	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	17926000	USD
CY2016	us-gaap	Adjustments To Additional Paid In Capital Stock Issued Issuance Costs AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts	1566000	USD
CY2015Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1741000	USD
CY2016Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	2392000	USD
CY2014	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	1641000	USD
CY2015	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	5617000	USD
CY2016	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	3861000	USD
CY2014	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	2127000	USD
CY2015	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	6364000	USD
CY2016	us-gaap	Amortization Of Financing Costs And Discounts AmortizationOfFinancingCostsAndDiscounts	6180000	USD
CY2014	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	221000	USD
CY2015	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	230000	USD
CY2016	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	510000	USD
CY2014	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	81000	shares
CY2015	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	6552000	shares
CY2016	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	3000	shares
CY2014Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	47386000	USD
CY2015Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	44735000	USD
CY2016Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	69639000	USD
CY2015	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	2560000	USD
CY2016	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	3186000	USD
CY2015	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	828000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred	3000	USD
CY2015	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	4693000	USD
CY2016	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled	2154000	USD
CY2015	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-1346000	USD
CY2016	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	1457000	USD
CY2015Q4	us-gaap	Assets Assets	4626643000	USD
CY2016Q4	us-gaap	Assets Assets	6515444000	USD
CY2015Q4	us-gaap	Assets Current AssetsCurrent	806477000	USD
CY2016Q4	us-gaap	Assets Current AssetsCurrent	466814000	USD
CY2015Q4	us-gaap	Assets Noncurrent AssetsNoncurrent	549087000	USD
CY2016Q4	us-gaap	Assets Noncurrent AssetsNoncurrent	1567080000	USD
CY2014	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	52584000	USD
CY2015	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	40250000	USD
CY2016	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	29082000	USD
CY2014Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	612012000	USD
CY2015Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	888775000	USD
CY2016Q4	us-gaap	Capitalized Costs Accumulated Depreciation Depletion Amortization And Valuation Allowance For Relating To Oil And Gas Producing Activities CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	1000091000	USD
CY2016	us-gaap	Capitalized Costs Of Unproved Properties Excluded From Amortization CapitalizedCostsOfUnprovedPropertiesExcludedFromAmortization	18547000	USD
CY2014Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	882847000	USD
CY2015Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	1055720000	USD
CY2016Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Gross CapitalizedCostsOilAndGasProducingActivitiesGross	1062105000	USD
CY2014Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	270835000	USD
CY2015Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	166945000	USD
CY2016Q4	us-gaap	Capitalized Costs Oil And Gas Producing Activities Net CapitalizedCostsOilAndGasProducingActivitiesNet	62014000	USD
CY2014Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	807518000	USD
CY2015Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	1008466000	USD
CY2016Q4	us-gaap	Capitalized Costs Proved Properties CapitalizedCostsProvedProperties	1043558000	USD
CY2014Q4	us-gaap	Capitalized Costs Unproved Properties CapitalizedCostsUnprovedProperties	75329000	USD
CY2015Q4	us-gaap	Capitalized Costs Unproved Properties CapitalizedCostsUnprovedProperties	47254000	USD
CY2016Q4	us-gaap	Capitalized Costs Unproved Properties CapitalizedCostsUnprovedProperties	18547000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	440861000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	13580000	USD
CY2013Q4	us-gaap	Cash And Cash Equivalents At Carrying Value Including Discontinued Operations CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations	4016000	USD
CY2014Q4	us-gaap	Cash And Cash Equivalents At Carrying Value Including Discontinued Operations CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations	9253000	USD
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value Including Discontinued Operations CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations	440861000	USD
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value Including Discontinued Operations CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations	13580000	USD
CY2014	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	5237000	USD
CY2015	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	431608000	USD
CY2016	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	-427281000	USD
CY2016Q4	us-gaap	Commercial Paper CommercialPaper	750000000	USD
CY2015Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2016Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies		USD
CY2014	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.56
CY2015Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.405
CY2015Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.405
CY2015Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.405
CY2015Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.405
CY2015	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.62
CY2016Q1	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.420
CY2016Q2	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.420
CY2016Q3	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.420
CY2016Q4	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	0.420
CY2016	us-gaap	Common Stock Dividends Per Share Cash Paid CommonStockDividendsPerShareCashPaid	1.68
CY2015Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.00
CY2016Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.00
CY2015Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2016Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	100000000	shares
CY2015Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	51231861	shares
CY2016Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	53397467	shares
CY2015Q4	us-gaap	Common Stock Value CommonStockValue	51232000	USD
CY2016Q4	us-gaap	Common Stock Value CommonStockValue	53397000	USD
CY2014	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	133267000	USD
CY2015	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	-26122000	USD
CY2016	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	47142000	USD
CY2014	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	133267000	USD
CY2015	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-26122000	USD
CY2016	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	56803000	USD
CY2014	us-gaap	Costs And Expenses CostsAndExpenses	403175000	USD
CY2015	us-gaap	Costs And Expenses CostsAndExpenses	412945000	USD
CY2016	us-gaap	Costs And Expenses CostsAndExpenses	555256000	USD
CY2014	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-2319000	USD
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	2549000	USD
CY2016	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-23820000	USD
CY2014	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-3607000	USD
CY2015	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	3868000	USD
CY2016	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	-25742000	USD
CY2014	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-1288000	USD
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1319000	USD
CY2016	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	-1922000	USD
CY2015Q4	us-gaap	Customer Advances And Deposits Current CustomerAdvancesAndDepositsCurrent	53496000	USD
CY2016Q4	us-gaap	Customer Advances And Deposits Current CustomerAdvancesAndDepositsCurrent	51628000	USD
CY2014	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	0	USD
CY2015	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	0	USD
CY2016	us-gaap	Decrease Due To Sales Of Minerals In Place DecreaseDueToSalesOfMineralsInPlace	9201000	USD
CY2014	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	64780000	USD
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	-23592000	USD
CY2016	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	36012000	USD
CY2015Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	13184000	USD
CY2016Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	21822000	USD
CY2016Q4	us-gaap	Deferred Finance Costs Noncurrent Net DeferredFinanceCostsNoncurrentNet	21822000	USD
CY2014	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	70232000	USD
CY2015	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-26028000	USD
CY2016	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	36217000	USD
CY2015Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	820090000	USD
CY2016Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	950446000	USD
CY2014	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	5658000	USD
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	-2323000	USD
CY2016	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	257000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	369511000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	414840000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	217922000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	252780000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	85907000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	83485000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	43586000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	58200000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	26400000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	29638000	USD
CY2015Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	4304000	USD
CY2016Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	9263000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	450579000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	535606000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Deferred Expense DeferredTaxLiabilitiesDeferredExpense	26121000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Deferred Expense DeferredTaxLiabilitiesDeferredExpense	18551000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	450579000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	535606000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	18519000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	14326000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	711293000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	820111000	USD
CY2015Q4	us-gaap	Deferred Tax Liabilities Regulatory Assets DeferredTaxLiabilitiesRegulatoryAssets	29092000	USD
CY2016Q4	us-gaap	Deferred Tax Liabilities Regulatory Assets DeferredTaxLiabilitiesRegulatoryAssets	49471000	USD
CY2016	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Accumulated Postretirement Benefit Obligation1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnAccumulatedPostretirementBenefitObligation1	2191000	USD
CY2016	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Decrease On Service And Interest Cost Components1 DefinedBenefitPlanEffectOfOnePercentagePointDecreaseOnServiceAndInterestCostComponents1	131000	USD
CY2016	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Accumulated Postretirement Benefit Obligation DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnAccumulatedPostretirementBenefitObligation	2569000	USD
CY2016	us-gaap	Defined Benefit Plan Effect Of One Percentage Point Increase On Service And Interest Cost Components DefinedBenefitPlanEffectOfOnePercentagePointIncreaseOnServiceAndInterestCostComponents	156000	USD
CY2015	us-gaap	Defined Benefit Plan Target Plan Asset Allocations DefinedBenefitPlanTargetPlanAssetAllocations	1
CY2016	us-gaap	Defined Benefit Plan Target Plan Asset Allocations DefinedBenefitPlanTargetPlanAssetAllocations	1
CY2016	us-gaap	Defined Benefit Plans Estimated Future Employer Contributions In Next Fiscal Year DefinedBenefitPlansEstimatedFutureEmployerContributionsInNextFiscalYear	10000000	USD
CY2016	us-gaap	Defined Contribution Plan Employers Matching Contribution Annual Vesting Percentage DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage	0.2
CY2016	us-gaap	Defined Contribution Plan Maximum Annual Contributions Per Employee Percent DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent	0.5
CY2014	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	144745000	USD
CY2015	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	155370000	USD
CY2016	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	189043000	USD
CY2015Q4	us-gaap	Derivative Assets DerivativeAssets	3441000	USD
CY2016Q4	us-gaap	Derivative Assets DerivativeAssets	4360000	USD
CY2015Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	0	USD
CY2016Q4	us-gaap	Derivative Assets Current DerivativeAssetsCurrent	4138000	USD
CY2015Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	3441000	USD
CY2016Q4	us-gaap	Derivative Assets Noncurrent DerivativeAssetsNoncurrent	222000	USD
CY2015Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	16378000	USD
CY2016Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	10355000	USD
CY2015Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	28132000	USD
CY2016Q4	us-gaap	Derivative Fair Value Of Derivative Liability DerivativeFairValueOfDerivativeLiability	13877000	USD
CY2016	us-gaap	Derivative Instruments Gain Loss Recognized In Income Ineffective Portion And Amount Excluded From Effectiveness Testing Net DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet	1000000	USD
CY2016	us-gaap	Derivative Instruments Loss Reclassified From Accumulated Oci Into Income Effective Portion DerivativeInstrumentsLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortion	28000000	USD
CY2015Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	2991000	USD
CY2016Q4	us-gaap	Derivative Liabilities DerivativeLiabilities	2733000	USD
CY2015Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	2835000	USD
CY2016Q4	us-gaap	Derivative Liabilities Current DerivativeLiabilitiesCurrent	2459000	USD
CY2015Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	156000	USD
CY2016Q4	us-gaap	Derivative Liabilities Noncurrent DerivativeLiabilitiesNoncurrent	274000	USD
CY2014	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	69636000	USD
CY2015	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	72604000	USD
CY2016	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	87570000	USD
CY2014	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.95
CY2015Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.76
CY2015Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.94
CY2015Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.22
CY2015Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.30
CY2015	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	-0.71
CY2016Q1	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.78
CY2016Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.01
CY2016Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.27
CY2016Q4	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.34
CY2016	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.41
CY2014	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.93
CY2015Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.76
CY2015Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.94
CY2015Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.22
CY2015Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.30
CY2015	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-0.71
CY2016Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.77
CY2016Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	800000	USD
CY2016Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.01
CY2016Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.26
CY2016Q4	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.33
CY2016	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.37
CY2014	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.337
CY2015	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.408
CY2016	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.113
CY2014	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2015	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2016	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.350
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Minority Interest Income Expense EffectiveIncomeTaxRateReconciliationMinorityInterestIncomeExpense	0.000
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Minority Interest Income Expense EffectiveIncomeTaxRateReconciliationMinorityInterestIncomeExpense	0.000
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Minority Interest Income Expense EffectiveIncomeTaxRateReconciliationMinorityInterestIncomeExpense	0.036
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Depletion EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepletion	-0.010
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Depletion EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepletion	0.035
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Depletion EffectiveIncomeTaxRateReconciliationNondeductibleExpenseDepletion	-0.082
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.000
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.000
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Nondeductible Expense Restructuring Charges EffectiveIncomeTaxRateReconciliationNondeductibleExpenseRestructuringCharges	0.011
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	-0.001
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.000
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Other Adjustments EffectiveIncomeTaxRateReconciliationOtherAdjustments	0.006
CY2014	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.011
CY2015	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.010
CY2016	us-gaap	Effective Income Tax Rate Reconciliation State And Local Income Taxes EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes	0.002
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies EffectiveIncomeTaxRateReconciliationTaxContingencies	-0.001
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies EffectiveIncomeTaxRateReconciliationTaxContingencies	-0.035
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Tax Contingencies EffectiveIncomeTaxRateReconciliationTaxContingencies	-0.060
CY2014	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.001
CY2015	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	-0.005
CY2016	us-gaap	Effective Income Tax Rate Reconciliation Tax Credits EffectiveIncomeTaxRateReconciliationTaxCredits	0.015
CY2015Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	43342000	USD
CY2016Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	56926000	USD
CY2016Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	13500000	USD
CY2016	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y
CY2015Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	25650000	USD
CY2016Q4	us-gaap	Energy Related Inventory Natural Gas In Storage EnergyRelatedInventoryNaturalGasInStorage	35087000	USD
CY2015Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	5567000	USD
CY2016Q4	us-gaap	Energy Related Inventory Other Fossil Fuel EnergyRelatedInventoryOtherFossilFuel	3667000	USD
CY2014	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	0	USD
CY2015	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	4405000	USD
CY2016	us-gaap	Equity Method Investment Other Than Temporary Impairment EquityMethodInvestmentOtherThanTemporaryImpairment	0	USD
CY2016	us-gaap	Exploration Costs ExplorationCosts	7416000	USD
CY2014	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	17582000	USD
CY2015	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	15718000	USD
CY2016	us-gaap	Extensions Discoveries Additions And Improved Recovery Less Related Costs ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts	0	USD
CY2016Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	800000	USD
CY2016Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	800000	USD
CY2016Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	800000	USD
CY2016Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	800000	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	675973000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	295173000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Cash Inflows FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows	246221000	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	45123000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	24833000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Development Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesDevelopmentCosts	18333000	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	29523000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	0	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Income Tax Expense FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense	0	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	356147000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	123788000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Net Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows	61640000	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	245180000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	146552000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Production Costs FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts	166248000	USD
CY2014Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	173125000	USD
CY2015Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	44760000	USD
CY2016Q4	us-gaap	Future Net Cash Flows Relating To Proved Oil And Gas Reserves Ten Percent Annual Discount For Estimated Timing Of Cash Flows FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows	26574000	USD
CY2014	us-gaap	Gain Loss On Sale Of Derivatives GainLossOnSaleOfDerivatives	0	USD
CY2015	us-gaap	Gain Loss On Sale Of Derivatives GainLossOnSaleOfDerivatives	0	USD
CY2016	us-gaap	Gain Loss On Sale Of Derivatives GainLossOnSaleOfDerivatives	28820000	USD
CY2016Q4	us-gaap	Gas And Oil Area Undeveloped Net GasAndOilAreaUndevelopedNet	127919	acre
CY2014Q4	us-gaap	Goodwill Goodwill	353396000	USD
CY2015Q4	us-gaap	Goodwill Goodwill	359759000	USD
CY2016Q4	us-gaap	Goodwill Goodwill	1299454000	USD
CY2015	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	6363000	USD
CY2016	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	939695000	USD
CY2016Q4	us-gaap	Guarantee Obligations Maximum Exposure GuaranteeObligationsMaximumExposure	57105000	USD
CY2014	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	0	USD
CY2015	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	249608000	USD
CY2016	us-gaap	Impairment Of Long Lived Assets Held For Use ImpairmentOfLongLivedAssetsHeldForUse	106957000	USD
CY2014	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	0	USD
CY2015	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	254013000	USD
CY2016	us-gaap	Impairment Of Oil And Gas Properties ImpairmentOfOilAndGasProperties	106957000	USD
CY2015Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	33850000	USD
CY2015Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-41842000	USD
CY2015Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-9943000	USD
CY2015Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-14176000	USD
CY2016Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	40050000	USD
CY2016Q2	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	3283000	USD
CY2016Q3	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	17884000	USD
CY2016Q4	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	21414000	USD
CY2014	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	197515000	USD
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-49522000	USD
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	93106000	USD
CY2014	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-1000	USD
CY2015	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-344000	USD
CY2016	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	0	USD
CY2014	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	66625000	USD
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-22160000	USD
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	10475000	USD
CY2014	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	413000	USD
CY2015	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1202000	USD
CY2016	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1156000	USD
CY2015Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	368000	USD
CY2016Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	0	USD
CY2014	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	18684000	USD
CY2015	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	-40125000	USD
CY2016	us-gaap	Increase Decrease In Accounts Receivable And Other Operating Assets IncreaseDecreaseInAccountsReceivableAndOtherOperatingAssets	28414000	USD
CY2014	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	3195000	USD
CY2015	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	-7387000	USD
CY2016	us-gaap	Increase Decrease In Estimated Future Development Costs IncreaseDecreaseInEstimatedFutureDevelopmentCosts	1825000	USD
CY2014	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	19265000	USD
CY2015	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	5682000	USD
CY2016	us-gaap	Increase Decrease In Future Income Tax Expense Estimates On Future Cash Flows Related To Proved Oil And Gas Reserves IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves	0	USD
CY2014	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	4563000	USD
CY2015	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-7197000	USD
CY2016	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-1099000	USD
CY2014	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	7887000	USD
CY2015	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	-4779000	USD
CY2016	us-gaap	Increase Decrease In Other Accounts Payable And Accrued Liabilities IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities	-40195000	USD
CY2014	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-733000	USD
CY2015	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	9034000	USD
CY2016	us-gaap	Increase Decrease In Other Operating Capital Net IncreaseDecreaseInOtherOperatingCapitalNet	-775000	USD
CY2014	us-gaap	Increase Decrease In Other Regulatory Assets IncreaseDecreaseInOtherRegulatoryAssets	38774000	USD
CY2015	us-gaap	Increase Decrease In Other Regulatory Assets IncreaseDecreaseInOtherRegulatoryAssets	-21883000	USD
CY2016	us-gaap	Increase Decrease In Other Regulatory Assets IncreaseDecreaseInOtherRegulatoryAssets	-3614000	USD
CY2014	us-gaap	Increase Decrease In Regulatory Liabilities IncreaseDecreaseInRegulatoryLiabilities	-7633000	USD
CY2015	us-gaap	Increase Decrease In Regulatory Liabilities IncreaseDecreaseInRegulatoryLiabilities	1675000	USD
CY2016	us-gaap	Increase Decrease In Regulatory Liabilities IncreaseDecreaseInRegulatoryLiabilities	-14082000	USD
CY2014	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	0	USD
CY2015	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	0	USD
CY2016	us-gaap	Increase Due To Purchases Of Minerals In Place IncreaseDueToPurchasesOfMineralsInPlace	0	USD
CY2014	us-gaap	Incremental Common Shares Attributable To Equity Unit Purchase Agreements IncrementalCommonSharesAttributableToEquityUnitPurchaseAgreements	0	shares
CY2015	us-gaap	Incremental Common Shares Attributable To Equity Unit Purchase Agreements IncrementalCommonSharesAttributableToEquityUnitPurchaseAgreements	0	shares
CY2016	us-gaap	Incremental Common Shares Attributable To Equity Unit Purchase Agreements IncrementalCommonSharesAttributableToEquityUnitPurchaseAgreements	1222000	shares
CY2014	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	204000	shares
CY2015	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	0	shares
CY2016	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	127000	shares
CY2013Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	3397000	USD
CY2014Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	3176000	USD
CY2015Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	3380000	USD
CY2016Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	8392000	USD
CY2014	us-gaap	Interest Costs Incurred InterestCostsIncurred	73017000	USD
CY2015	us-gaap	Interest Costs Incurred InterestCostsIncurred	86278000	USD
CY2016	us-gaap	Interest Costs Incurred InterestCostsIncurred	139590000	USD
CY2014	us-gaap	Interest Expense InterestExpense	70960000	USD
CY2015	us-gaap	Interest Expense InterestExpense	83719000	USD
CY2016	us-gaap	Interest Expense InterestExpense	135412000	USD
CY2014	us-gaap	Interest Paid Net InterestPaidNet	69239000	USD
CY2015	us-gaap	Interest Paid Net InterestPaidNet	77810000	USD
CY2016	us-gaap	Interest Paid Net InterestPaidNet	112925000	USD
CY2015Q4	us-gaap	Interest Payable Current InterestPayableCurrent	25762000	USD
CY2016Q4	us-gaap	Interest Payable Current InterestPayableCurrent	45503000	USD
CY2015Q4	us-gaap	Inventory Net InventoryNet	86943000	USD
CY2016Q4	us-gaap	Inventory Net InventoryNet	107210000	USD
CY2015Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	55726000	USD
CY2016Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	68456000	USD
CY2014	us-gaap	Investment Income Interest InvestmentIncomeInterest	1925000	USD
CY2015	us-gaap	Investment Income Interest InvestmentIncomeInterest	1621000	USD
CY2016	us-gaap	Investment Income Interest InvestmentIncomeInterest	1429000	USD
CY2014	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	6932000	USD
CY2015	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	7177000	USD
CY2016	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	9568000	USD
CY2015Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	4626643000	USD
CY2016Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	6515444000	USD
CY2015Q4	us-gaap	Liabilities Current LiabilitiesCurrent	406355000	USD
CY2016Q4	us-gaap	Liabilities Current LiabilitiesCurrent	527932000	USD
CY2015Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	900739000	USD
CY2016Q4	us-gaap	Liabilities Noncurrent LiabilitiesNoncurrent	1041894000	USD
CY2013Q4	us-gaap	Liability For Uncertain Tax Positions Noncurrent LiabilityForUncertainTaxPositionsNoncurrent	37631000	USD
CY2014Q4	us-gaap	Liability For Uncertain Tax Positions Noncurrent LiabilityForUncertainTaxPositionsNoncurrent	32192000	USD
CY2015Q4	us-gaap	Liability For Uncertain Tax Positions Noncurrent LiabilityForUncertainTaxPositionsNoncurrent	31986000	USD
CY2016Q4	us-gaap	Liability For Uncertain Tax Positions Noncurrent LiabilityForUncertainTaxPositionsNoncurrent	3592000	USD
CY2015Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	0	USD
CY2016Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	5743000	USD
CY2016Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	2361855000	USD
CY2016Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	8436000	USD
CY2016Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	205742000	USD
CY2016Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	655742000	USD
CY2016Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	5743000	USD
CY2015Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	1853682000	USD
CY2016Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	3211189000	USD
CY2015Q4	us-gaap	Long Term Investments LongTermInvestments	11985000	USD
CY2016Q4	us-gaap	Long Term Investments LongTermInvestments	12561000	USD
CY2015Q4	us-gaap	Loss Contingency Accrual Carrying Value Current LossContingencyAccrualCarryingValueCurrent	38750000	USD
CY2016Q4	us-gaap	Loss Contingency Accrual Carrying Value Current LossContingencyAccrualCarryingValueCurrent	0	USD
CY2016	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	9561000	USD
CY2016Q4	us-gaap	Minority Interest Ownership Percentage By Noncontrolling Owners MinorityInterestOwnershipPercentageByNoncontrollingOwners	0.005
CY2014	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	91067000	USD
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	483702000	USD
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	840998000	USD
CY2014	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-401147000	USD
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-476389000	USD
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-1588742000	USD
CY2014	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	315317000	USD
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	424295000	USD
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	320463000	USD
CY2014	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2015	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	0	USD
CY2016	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	9661000	USD
CY2014	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	130889000	USD
CY2015Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	33850000	USD
CY2015Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-41842000	USD
CY2015Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-9943000	USD
CY2015Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-14176000	USD
CY2015	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-32111000	USD
CY2016Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	40002000	USD
CY2016Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	669000	USD
CY2016Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	14131000	USD
CY2016Q4	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	18168000	USD
CY2016	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	72970000	USD
CY2014	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-28544000	USD
CY2015	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-127199000	USD
CY2016	us-gaap	Net Increase Decrease In Sales And Transfer Prices And Production Costs NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts	-32698000	USD
CY2015Q4	us-gaap	Noncontrolling Interest In Variable Interest Entity NoncontrollingInterestInVariableInterestEntity	0	USD
CY2016Q4	us-gaap	Noncontrolling Interest In Variable Interest Entity NoncontrollingInterestInVariableInterestEntity	115495000	USD
CY2016	us-gaap	Noncontrolling Interest Increase From Sale Of Parent Equity Interest NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest	177233000	USD
CY2016Q4	us-gaap	Oil And Gas Property Full Cost Method Net OilAndGasPropertyFullCostMethodNet	43000000	USD
CY2014	us-gaap	Operating Expenses OperatingExpenses	1129702000	USD
CY2015	us-gaap	Operating Expenses OperatingExpenses	1274810000	USD
CY2016	us-gaap	Operating Expenses OperatingExpenses	1350388000	USD
CY2014	us-gaap	Operating Income Loss OperatingIncomeLoss	263868000	USD
CY2015Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	70500000	USD
CY2015Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	-38858000	USD
CY2015Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	-2044000	USD
CY2015Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	197000	USD
CY2015	us-gaap	Operating Income Loss OperatingIncomeLoss	29795000	USD
CY2016Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	73590000	USD
CY2016Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	58409000	USD
CY2016Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	55289000	USD
CY2016	us-gaap	Operating Income Loss OperatingIncomeLoss	222586000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	6739000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	1652000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	2639000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	4441000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	5564000	USD
CY2016Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	6245000	USD
CY2015Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	38318000	USD
CY2016Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	49973000	USD
CY2015Q4	us-gaap	Other Assets Current OtherAssetsCurrent	71763000	USD
CY2016Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	35298000	USD
CY2016Q4	us-gaap	Other Assets Current OtherAssetsCurrent	27063000	USD
CY2015Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	7382000	USD
CY2016Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	12130000	USD
CY2014	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Costs Credit Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax	-237000	USD
CY2015	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Costs Credit Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax	0	USD
CY2016	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Costs Credit Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostsCreditArisingDuringPeriodNetOfTax	247000	USD
CY2014	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-10590000	USD
CY2015	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	2657000	USD
CY2016	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Net Of Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodNetOfTax	-1738000	USD
CY2014	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-5004000	USD
CY2015	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	1375000	USD
CY2016	us-gaap	Other Comprehensive Income Defined Benefit Plans Net Unamortized Gain Loss Arising During Period Tax OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax	-757000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-141000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-150000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Net Of Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditNetOfTax	-154000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-76000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-88000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditTax	-67000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	2378000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	5989000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-25828000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Benefit Plan Improvement Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect	-17000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Benefit Plan Improvement Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect	0	USD
CY2016	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Benefit Plan Improvement Tax Effect OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansBenefitPlanImprovementTaxEffect	107000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-348000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-972000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-600000	USD
CY2014	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-646000	USD
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1850000	USD
CY2016	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1378000	USD
CY2014	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	500000	USD
CY2015	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	7483000	USD
CY2016	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	50335000	USD
CY2015Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	155369000	USD
CY2016Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	138643000	USD
CY2014	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-14415000	USD
CY2015	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	4872000	USD
CY2016	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	5518000	USD
CY2014	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	377000	USD
CY2015	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	372000	USD
CY2016	us-gaap	Other Nonoperating Expense OtherNonoperatingExpense	609000	USD
CY2014	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	2065000	USD
CY2015	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	2256000	USD
CY2016	us-gaap	Other Nonoperating Income OtherNonoperatingIncome	1842000	USD
CY2014	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	2681000	USD
CY2015	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	2437000	USD
CY2016	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	4503000	USD
CY2014	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	2653000	USD
CY2015	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	-1062000	USD
CY2016	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	1139000	USD
CY2014	us-gaap	Payments Of Dividends PaymentsOfDividends	69636000	USD
CY2015	us-gaap	Payments Of Dividends PaymentsOfDividends	72604000	USD
CY2016	us-gaap	Payments Of Dividends PaymentsOfDividends	87570000	USD
CY2014	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	398494000	USD
CY2015	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	455481000	USD
CY2016	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	474783000	USD
CY2014	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	0	USD
CY2015	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	0	USD
CY2016	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	9561000	USD
CY2014	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	14814000	USD
CY2015	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	20616000	USD
CY2016	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	14291000	USD
CY2015Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	146459000	USD
CY2016Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	173682000	USD
CY2014	us-gaap	Pension Contributions PensionContributions	10200000	USD
CY2015	us-gaap	Pension Contributions PensionContributions	10200000	USD
CY2016	us-gaap	Pension Contributions PensionContributions	14200000	USD
CY2016Q4	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2016Q4	us-gaap	Preferred Stock Shares Outstanding PreferredStockSharesOutstanding	0	shares
CY2014	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	2079000	USD
CY2015	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	27211000	USD
CY2016	us-gaap	Previously Estimated Development Costs Incurred PreviouslyEstimatedDevelopmentCostsIncurred	0	USD
CY2015Q4	us-gaap	Proceeds From Convertible Debt ProceedsFromConvertibleDebt	299000000	USD
CY2014	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	3251000	USD
CY2015	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	248759000	USD
CY2016	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	121619000	USD
CY2016Q1	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	546000000	USD
CY2014	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	160000000	USD
CY2015	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	300000000	USD
CY2016	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	1767608000	USD
CY2014	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	396250000	USD
CY2015	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	397310000	USD
CY2016	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	425400000	USD
CY2014	us-gaap	Proceeds From Minority Shareholders ProceedsFromMinorityShareholders	0	USD
CY2015	us-gaap	Proceeds From Minority Shareholders ProceedsFromMinorityShareholders	0	USD
CY2016	us-gaap	Proceeds From Minority Shareholders ProceedsFromMinorityShareholders	216370000	USD
CY2014	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	17152000	USD
CY2015	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-9283000	USD
CY2016	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-22960000	USD
CY2015Q4	us-gaap	Proceeds From Sale Of Interest In Corporate Unit ProceedsFromSaleOfInterestInCorporateUnit	290030000	USD
CY2014	us-gaap	Proceeds From Sale Of Interest In Corporate Unit ProceedsFromSaleOfInterestInCorporateUnit	0	USD
CY2015	us-gaap	Proceeds From Sale Of Interest In Corporate Unit ProceedsFromSaleOfInterestInCorporateUnit	290030000	USD
CY2016	us-gaap	Proceeds From Sale Of Interest In Corporate Unit ProceedsFromSaleOfInterestInCorporateUnit	0	USD
CY2014	us-gaap	Proceeds From Sale Of Other Assets Investing Activities ProceedsFromSaleOfOtherAssetsInvestingActivities	0	USD
CY2015	us-gaap	Proceeds From Sale Of Other Assets Investing Activities ProceedsFromSaleOfOtherAssetsInvestingActivities	0	USD
CY2016	us-gaap	Proceeds From Sale Of Other Assets Investing Activities ProceedsFromSaleOfOtherAssetsInvestingActivities	11418000	USD
CY2014	us-gaap	Profit Loss ProfitLoss	130889000	USD
CY2015	us-gaap	Profit Loss ProfitLoss	-32111000	USD
CY2016	us-gaap	Profit Loss ProfitLoss	82631000	USD
CY2015Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	4976778000	USD
CY2016Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	6412223000	USD
CY2015	us-gaap	Property Plant And Equipment Gross Period Increase Decrease PropertyPlantAndEquipmentGrossPeriodIncreaseDecrease	458821000	USD
CY2016	us-gaap	Property Plant And Equipment Gross Period Increase Decrease PropertyPlantAndEquipmentGrossPeriodIncreaseDecrease	467119000	USD
CY2015Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	3259094000	USD
CY2016Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	4468989000	USD
CY2016Q4	us-gaap	Proved Developed Reserves Boe1 ProvedDevelopedReservesBOE1	0	Mcfe
CY2014	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	994000	USD
CY2015	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	897000	USD
CY2016	us-gaap	Public Utilities Allowance For Funds Used During Construction Capitalized Cost Of Equity PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity	3270000	USD
CY2015Q4	us-gaap	Redeemable Noncontrolling Interest Equity Other Carrying Amount RedeemableNoncontrollingInterestEquityOtherCarryingAmount	0	USD
CY2016Q4	us-gaap	Redeemable Noncontrolling Interest Equity Other Carrying Amount RedeemableNoncontrollingInterestEquityOtherCarryingAmount	4295000	USD
CY2015Q4	us-gaap	Regulatory Assets RegulatoryAssets	232484000	USD
CY2016Q4	us-gaap	Regulatory Assets RegulatoryAssets	296142000	USD
CY2015Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	57359000	USD
CY2016Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	49260000	USD
CY2015Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	175125000	USD
CY2016Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	246882000	USD
CY2015Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	153041000	USD
CY2016Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	206756000	USD
CY2015Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	4865000	USD
CY2016Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	13067000	USD
CY2015Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	148176000	USD
CY2016Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	193689000	USD
CY2014	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	403750000	USD
CY2015	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	395510000	USD
CY2016	us-gaap	Repayments Of Lines Of Credit RepaymentsOfLinesOfCredit	405600000	USD
CY2014	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	12200000	USD
CY2015	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	275000000	USD
CY2016	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	1164308000	USD
CY2015Q4	us-gaap	Restricted Cash And Investments Current RestrictedCashAndInvestmentsCurrent	1697000	USD
CY2016Q4	us-gaap	Restricted Cash And Investments Current RestrictedCashAndInvestmentsCurrent	2274000	USD
CY2014	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	23288000	USD
CY2015	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	28062000	USD
CY2016	us-gaap	Results Of Operations Depreciation Depletion And Amortization And Valuation Provisions ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions	12574000	USD
CY2014	us-gaap	Results Of Operations Expense From Oil And Gas Producing Activities ResultsOfOperationsExpenseFromOilAndGasProducingActivities	45443000	USD
CY2015	us-gaap	Results Of Operations Expense From Oil And Gas Producing Activities ResultsOfOperationsExpenseFromOilAndGasProducingActivities	297432000	USD
CY2016	us-gaap	Results Of Operations Expense From Oil And Gas Producing Activities ResultsOfOperationsExpenseFromOilAndGasProducingActivities	136762000	USD
CY2014	us-gaap	Results Of Operations Impairment Of Oil And Gas Properties ResultsOfOperationsImpairmentOfOilAndGasProperties	0	USD
CY2015	us-gaap	Results Of Operations Impairment Of Oil And Gas Properties ResultsOfOperationsImpairmentOfOilAndGasProperties	249608000	USD
CY2016	us-gaap	Results Of Operations Impairment Of Oil And Gas Properties ResultsOfOperationsImpairmentOfOilAndGasProperties	106957000	USD
CY2014	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	9671000	USD
CY2015	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	-254149000	USD
CY2016	us-gaap	Results Of Operations Income Before Income Taxes ResultsOfOperationsIncomeBeforeIncomeTaxes	-102704000	USD
CY2014	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	3415000	USD
CY2015	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	-93743000	USD
CY2016	us-gaap	Results Of Operations Income Tax Expense ResultsOfOperationsIncomeTaxExpense	-37916000	USD
CY2014	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	6256000	USD
CY2015	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	-160406000	USD
CY2016	us-gaap	Results Of Operations Oil And Gas Producing Activities Net Income Excluding Corporate Overhead And Interest Costs ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts	-64788000	USD
CY2014	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	22155000	USD
CY2015	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	19762000	USD
CY2016	us-gaap	Results Of Operations Production Or Lifting Costs ResultsOfOperationsProductionOrLiftingCosts	17231000	USD
CY2014	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	55114000	USD
CY2015	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	43283000	USD
CY2016	us-gaap	Results Of Operations Revenue From Oil And Gas Producing Activities ResultsOfOperationsRevenueFromOilAndGasProducingActivities	34058000	USD
CY2015Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	472534000	USD
CY2016Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	457934000	USD
CY2014	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	23722000	USD
CY2015	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	-6941000	USD
CY2016	us-gaap	Revisions Of Previous Quantity Estimates RevisionsOfPreviousQuantityEstimates	-7477000	USD
CY2014	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	32139000	USD
CY2015	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	29948000	USD
CY2016	us-gaap	Sales And Transfers Of Oil And Gas Produced Net Of Production Costs SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts	4314000	USD
CY2014	us-gaap	Sales Revenue Net SalesRevenueNet	1393570000	USD
CY2015Q1	us-gaap	Sales Revenue Net SalesRevenueNet	441987000	USD
CY2015Q2	us-gaap	Sales Revenue Net SalesRevenueNet	272254000	USD
CY2015Q3	us-gaap	Sales Revenue Net SalesRevenueNet	272105000	USD
CY2015Q4	us-gaap	Sales Revenue Net SalesRevenueNet	318259000	USD
CY2015	us-gaap	Sales Revenue Net SalesRevenueNet	1304605000	USD
CY2016Q1	us-gaap	Sales Revenue Net SalesRevenueNet	449959000	USD
CY2016Q2	us-gaap	Sales Revenue Net SalesRevenueNet	325441000	USD
CY2016Q3	us-gaap	Sales Revenue Net SalesRevenueNet	333786000	USD
CY2016Q4	us-gaap	Sales Revenue Net SalesRevenueNet	463788000	USD
CY2016	us-gaap	Sales Revenue Net SalesRevenueNet	1572974000	USD
CY2014	us-gaap	Share Based Compensation ShareBasedCompensation	9329000	USD
CY2015	us-gaap	Share Based Compensation ShareBasedCompensation	4076000	USD
CY2016	us-gaap	Share Based Compensation ShareBasedCompensation	10885000	USD
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant	1115557	shares
CY2015Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	76800000	USD
CY2016Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	96600000	USD
CY2014	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	18437000	USD
CY2015	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	18870000	USD
CY2016	us-gaap	Standardized Measure Of Discounted Future Net Cash Flow Relating To Proved Oil And Gas Reserves Accretion Of Discount StandardizedMeasureOfDiscountedFutureNetCashFlowRelatingToProvedOilAndGasReservesAccretionOfDiscount	7903000	USD
CY2013Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	159425000	USD
CY2014Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	183022000	USD
CY2015Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	79028000	USD
CY2016Q4	us-gaap	Standardized Measure Of Discounted Future Net Cash Flows Relating To Proved Oil And Gas Reserves StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves	35066000	USD
CY2014	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	2878000	USD
CY2015	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	2957000	USD
CY2016	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	2983000	USD
CY2015	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	254581000	USD
CY2016	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	119990000	USD
CY2014	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	4415000	USD
CY2015	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	4240000	USD
CY2016	us-gaap	Stock Issued During Period Value Share Based Compensation StockIssuedDuringPeriodValueShareBasedCompensation	5479000	USD
CY2015Q4	us-gaap	Stockholders Equity StockholdersEquity	1465867000	USD
CY2016Q4	us-gaap	Stockholders Equity StockholdersEquity	1614639000	USD
CY2013Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1283500000	USD
CY2014Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1353884000	USD
CY2015Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1465867000	USD
CY2016Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1730134000	USD
CY2014	us-gaap	Stockholders Equity Other StockholdersEquityOther	41000	USD
CY2015	us-gaap	Stockholders Equity Other StockholdersEquityOther	25000	USD
CY2016	us-gaap	Stockholders Equity Other StockholdersEquityOther	-476000	USD
CY2016	us-gaap	Subsidiary Or Equity Method Investee Cumulative Percentage Ownership After All Transactions SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions	0.995
CY2014	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	43580000	USD
CY2015	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	44353000	USD
CY2016	us-gaap	Taxes Excluding Income And Excise Taxes TaxesExcludingIncomeAndExciseTaxes	48522000	USD
CY2015Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	39720	shares
CY2016Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	15258	shares
CY2015Q4	us-gaap	Treasury Stock Value TreasuryStockValue	1888000	USD
CY2016Q4	us-gaap	Treasury Stock Value TreasuryStockValue	791000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	6692000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	3491000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	19174000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	0	USD
CY2016	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	11643000	USD
CY2015Q4	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Accrued UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued	13300000	USD
CY2014	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	1600000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	1800000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Income Tax Penalties And Interest Expense UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense	0	USD
CY2014	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	0	USD
CY2014	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	1253000	USD
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	3285000	USD
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	2423000	USD
CY2016Q4	us-gaap	Unrecognized Tax Benefits That Would Impact Effective Tax Rate UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate	700000	USD
CY2014	us-gaap	Valuation Allowances And Reserves Adjustments ValuationAllowancesAndReservesAdjustments	0	USD
CY2015	us-gaap	Valuation Allowances And Reserves Adjustments ValuationAllowancesAndReservesAdjustments	0	USD
CY2016	us-gaap	Valuation Allowances And Reserves Adjustments ValuationAllowancesAndReservesAdjustments	2158000	USD
CY2013Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1237000	USD
CY2014Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1516000	USD
CY2015Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	1741000	USD
CY2016Q4	us-gaap	Valuation Allowances And Reserves Balance ValuationAllowancesAndReservesBalance	2392000	USD
CY2014	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	4470000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	3860000	USD
CY2016	us-gaap	Valuation Allowances And Reserves Charged To Cost And Expense ValuationAllowancesAndReservesChargedToCostAndExpense	2704000	USD
CY2014	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	8424000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	7767000	USD
CY2016	us-gaap	Valuation Allowances And Reserves Deductions ValuationAllowancesAndReservesDeductions	9126000	USD
CY2014	us-gaap	Valuation Allowances And Reserves Recoveries ValuationAllowancesAndReservesRecoveries	4233000	USD
CY2015	us-gaap	Valuation Allowances And Reserves Recoveries ValuationAllowancesAndReservesRecoveries	4132000	USD
CY2016	us-gaap	Valuation Allowances And Reserves Recoveries ValuationAllowancesAndReservesRecoveries	4915000	USD
CY2014	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	44598000	shares
CY2015	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	45288000	shares
CY2016	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	53271000	shares
CY2014	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	44394000	shares
CY2015	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	45288000	shares
CY2016	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	51922000	shares
CY2016Q4	us-gaap	Wells In Process Of Drilling WellsInProcessOfDrilling	713
CY2016	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Revisions</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;padding-bottom:10px;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Certain revisions have been made to prior years’ financial information to conform to the current year presentation.</font></div><div style="line-height:120%;padding-bottom:10px;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Company revised its presentation of cash and book overdrafts.  For accounts with the same financial institution where there is a banking arrangement that clears payments with balances in other bank accounts, book overdrafts are presented on a combined basis by bank as cash and cash equivalents. Prior year amounts were corrected to conform with the current year presentation, which decreased cash and cash equivalents and accounts payable by </font><font style="font-family:inherit;font-size:10pt;">$16 million</font><font style="font-family:inherit;font-size:10pt;">, </font><font style="font-family:inherit;font-size:10pt;">$12 million</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;">$3.8 million</font><font style="font-family:inherit;font-size:10pt;"> as of December 31, 2015, December 31, 2014 and December 31, 2013, respectively, and decreased net cash flows provided by operations by </font><font style="font-family:inherit;font-size:10pt;">$3.7 million</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;">$8.1 million</font><font style="font-family:inherit;font-size:10pt;"> for the years ended December 31, 2015 and 2014 respectively. We assessed the materiality of these changes, taking into account quantitative and qualitative factors, and determined them to be immaterial to the consolidated balance sheet as of December 31, 2015 and to the consolidated statements of cash flows for the years ended December 31, 2015 and 2014. There is no impact to the Consolidated Statements of Income (Loss), the Consolidated Statements of Comprehensive Income (Loss) or the Consolidated Statements of Equity, for any period reported.</font></div></div>
CY2016	us-gaap	Property Plant And Equipment Preproduction Design And Development Costs PropertyPlantAndEquipmentPreproductionDesignAndDevelopmentCosts	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Development Costs</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">According to accounting standards for business combinations, we expense, when incurred, development and acquisition costs associated with corporate development activities prior to acquiring or beginning construction of a project. Expensed development costs are included in Other operating expenses on the accompanying Consolidated Statements of Income (Loss).</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></div>
CY2016	us-gaap	Reclassifications Reclassifications	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The following changes have been made to our Consolidated Statements of Income (Loss) to reflect combined revenue and combined operations and maintenance expenses, rather than by business group as previously reported, for the twelve months ended </font><font style="font-family:inherit;font-size:10pt;">December 31, 2015</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;">December 31, 2014</font><font style="font-family:inherit;font-size:10pt;"> respectively:</font></div><div style="line-height:120%;text-align:center;font-size:10pt;"><div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"><table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;margin-left:auto;margin-right:auto;width:99.41747572815534%;border-collapse:collapse;text-align:left;"><tr><td colspan="20" rowspan="1"></td></tr><tr><td style="width:25%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:10%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:11%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:10%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:10%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:11%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td><td style="width:10%;" rowspan="1" colspan="1"></td><td style="width:1%;" rowspan="1" colspan="1"></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="9" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">Year Ended December 31, 2015</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="9" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">Year Ended December 31, 2014</font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">(in thousands)</font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">As Previously Reported</font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">Presentation Reclassification</font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">As Currently Reported</font></div></td><td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">As Previously Reported</font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">Presentation Reclassification</font></div></td><td colspan="3" style="vertical-align:top;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="text-align:center;font-size:9pt;"><font style="font-family:inherit;font-size:9pt;">As Currently Reported</font></div></td></tr><tr><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Revenue:</font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;border-top:1px solid #000000;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Utilities</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,219,526</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(1,219,526</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,300,969</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(1,300,969</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Non-regulated energy</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">85,079</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(85,079</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">92,601</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(92,601</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Revenue</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,304,605</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,304,605</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,393,570</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">1,393,570</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;height:20px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Operating Expenses:</font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td colspan="3" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td></tr><tr><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Utilities - operations and maintenance</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">272,407</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(272,407</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">270,954</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(270,954</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Non-regulated energy operations and maintenance</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">88,702</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(88,702</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">88,141</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">(88,141</font></div></td><td style="vertical-align:bottom;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">)</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr><tr><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Operations and maintenance</font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">361,109</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">361,109</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"><div style="overflow:hidden;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"> </font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">—</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">359,095</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td><td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">$</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"><div style="text-align:right;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">359,095</font></div></td><td style="vertical-align:bottom;background-color:#ceffe7;" rowspan="1" colspan="1"><div style="text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div></td></tr></table></div></div></div>
CY2016	us-gaap	Use Of Estimates UseOfEstimates	<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Use of Estimates and Basis of Presentation</font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;"><br clear="none"/></font></div><div style="line-height:120%;text-align:left;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of certain assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Changes in facts and circumstances or additional information may result in revised estimates and actual results could differ materially from those estimates.</font></div></div>

Files In Submission

Name	View Source	Status
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0001130464-17-000010-index.html	Edgar Link	pending
0001130464-17-000010.txt	Edgar Link	pending
0001130464-17-000010-xbrl.zip	Edgar Link	pending
bkh-20161231.xml	Edgar Link	completed
bkh-20161231.xsd	Edgar Link	pending
bkh-20161231_cal.xml	Edgar Link	unprocessable
bkh-20161231_def.xml	Edgar Link	unprocessable
bkh-20161231_lab.xml	Edgar Link	unprocessable
bkh-20161231_pre.xml	Edgar Link	unprocessable
bkh10k122016.htm	Edgar Link	pending
bkhex-1022amdtocragrmt1220.htm	Edgar Link	pending
bkhex-1025amdtotermloanagr.htm	Edgar Link	pending
bkhex-21listofsubs122016.htm	Edgar Link	pending
bkhex-231auditconsent122016.htm	Edgar Link	pending
bkhex-232engineersconsent1.htm	Edgar Link	pending
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bkhex-312cfo122016.htm	Edgar Link	pending
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bkhex-95minesafetydata1220.htm	Edgar Link	pending
bkhex-99oilandgas122016.htm	Edgar Link	pending
FilingSummary.xml	Edgar Link	unprocessable
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2015 Q4 Form 10-K Financial Statement

#000113046417000010 Filed on February 27, 2017

Income Statement

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$BKH BLACK HILLS CORP /SD/ Stock $bkh

2015 Q4 Form 10-K Financial Statement

#000113046417000010 Filed on February 27, 2017

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$BKH
BLACK HILLS CORP /SD/ Stock $bkh