$OTTR
Otter Tail Corp Stock $ottr

$ottr Overview Financials Valuation SEC Filings Company Website

2017 Form 10-K Financial Statement

#000143774918002843 Filed on February 20, 2018

Income Statement

Concept	2017	2016 Q4	2016
Revenue	$849.4M	$196.6M	$803.5M
YoY Change	5.7%	4.13%	3.04%
Cost Of Revenue	$316.6M	$86.00M	$295.2M
YoY Change	7.23%	-0.23%	0.06%
Gross Profit	$532.8M	$110.6M	$508.3M
YoY Change	4.81%	7.8%	4.86%
Gross Profit Margin	62.73%	56.26%	63.26%
Selling, General & Admin
YoY Change
% of Gross Profit
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$72.55M	$18.30M	$73.45M
YoY Change	-1.23%	13.66%	21.67%
% of Gross Profit	13.62%	16.55%	14.45%
Operating Expenses	$335.7M	$81.50M	$334.0M
YoY Change	0.51%	11.95%	12.31%
Operating Profit	$132.3M	$29.10M	$116.6M
YoY Change	13.42%	-2.35%	6.79%
Interest Expense	-$29.60M	-$7.900M	-$31.90M
YoY Change	-7.21%	-1.25%	2.24%
% of Operating Profit	-22.38%	-27.15%	-27.35%
Other Income/Expense, Net	$2.632M	$500.0K	$2.905M
YoY Change	-9.4%	-28.57%	33.44%
Pretax Income	$99.70M	$21.70M	$82.54M
YoY Change	20.78%	-3.56%	2.88%
Income Tax	$27.26M	$4.300M	$20.22M
% Of Pretax Income	27.34%	19.82%	24.5%
Net Earnings	$72.44M	$17.50M	$62.32M
YoY Change	16.24%	19.86%	5.01%
Net Earnings / Revenue	8.53%	8.9%	7.76%
Basic Earnings Per Share	$1.84		$1.62
Diluted Earnings Per Share	$1.82	$441.9K	$1.61
COMMON SHARES
Basic Shares Outstanding	39.46M		38.55M
Diluted Shares Outstanding	39.75M		38.73M

Balance Sheet

Concept	2017	2016 Q4	2016
SHORT-TERM ASSETS
Cash & Short-Term Investments	$16.20M	$0.00	$0.00
YoY Change
Cash & Equivalents	$16.20M	$0.00	$0.00
Short-Term Investments
Other Short-Term Assets	$57.50M	$8.144M	$49.50M
YoY Change	16.16%	-81.98%	9.51%
Inventory	$88.00M	$83.74M	$83.70M
Prepaid Expenses
Receivables	$68.50M	$68.24M	$68.20M
Other Receivables	$8.900M	$5.850M	$6.600M
Total Short-Term Assets	$239.1M	$208.0M	$208.0M
YoY Change	14.95%	0.64%	0.63%
LONG-TERM ASSETS
Property, Plant & Equipment	$1.540B	$1.477B	$1.477B
YoY Change	4.22%	6.44%	6.45%
Goodwill		$37.57M
YoY Change		-5.44%
Intangibles		$14.96M
YoY Change
Long-Term Investments	$8.600M	$8.400M	$8.400M
YoY Change	2.38%	1.2%	1.2%
Other Assets	$165.6M	$34.10M	$166.2M
YoY Change	-0.36%	-78.75%	3.55%
Total Long-Term Assets	$1.765B	$1.704B	$1.704B
YoY Change	3.57%	5.73%	5.73%
TOTAL ASSETS
Total Short-Term Assets	$239.1M	$208.0M	$208.0M
Total Long-Term Assets	$1.765B	$1.704B	$1.704B
Total Assets	$2.004B	$1.912B	$1.912B
YoY Change	4.81%	5.15%	5.15%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$84.20M	$89.35M	$89.40M
YoY Change	-5.82%	-0.17%	-0.11%
Accrued Expenses	$32.90M	$32.90M	$32.90M
YoY Change	0.0%	4.78%	4.78%
Deferred Revenue
YoY Change
Short-Term Debt	$112.4M	$42.88M	$42.90M
YoY Change	162.0%	-46.86%	-46.84%
Long-Term Debt Due	$200.0K	$33.20M	$33.20M
YoY Change	-99.4%	-36.64%	-36.64%
Total Short-Term Liabilities	$256.7M	$215.7M	$215.7M
YoY Change	19.01%	-20.45%	-20.44%
LONG-TERM LIABILITIES
Long-Term Debt	$490.4M	$505.3M	$505.3M
YoY Change	-2.95%	13.87%	13.86%
Other Long-Term Liabilities	$438.5M	$21.71M	$271.8M
YoY Change	61.33%	-91.86%	1.99%
Total Long-Term Liabilities	$928.9M	$527.0M	$777.1M
YoY Change	19.53%	-25.8%	9.4%
TOTAL LIABILITIES
Total Short-Term Liabilities	$256.7M	$215.7M	$215.7M
Total Long-Term Liabilities	$928.9M	$527.0M	$777.1M
Total Liabilities	$1.307B	$742.7M	$1.242B
YoY Change	5.24%	-38.81%	2.36%
SHAREHOLDERS EQUITY
Retained Earnings		$139.5M
YoY Change
Common Stock		$534.4M
YoY Change
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$696.9M	$670.1M	$670.1M
YoY Change
Total Liabilities & Shareholders Equity	$2.004B	$1.912B	$1.912B
YoY Change	4.81%	5.15%	5.15%

Cashflow Statement

Concept	2017	2016 Q4	2016
OPERATING ACTIVITIES
Net Income	$72.44M	$17.50M	$62.32M
YoY Change	16.24%	19.86%	5.01%
Depreciation, Depletion And Amortization	$72.55M	$18.30M	$73.45M
YoY Change	-1.23%	13.66%	21.67%
Cash From Operating Activities	$173.6M	$48.70M	$163.4M
YoY Change	6.24%	2.96%	39.0%
INVESTING ACTIVITIES
Capital Expenditures	-$132.9M	-$35.40M	-$161.3M
YoY Change	-17.61%	-20.98%	0.75%
Acquisitions
YoY Change
Other Investing Activities	$300.0K	-$600.0K	$1.900M
YoY Change	-84.21%	-107.23%	-53.66%
Cash From Investing Activities	-$132.6M	-$35.90M	-$159.3M
YoY Change	-16.78%	-1.64%	2.15%
FINANCING ACTIVITIES
Cash Dividend Paid	$50.63M
YoY Change
Common Stock Issuance & Retirement, Net	-$2.550M		-$44.33M
YoY Change	-94.25%		263.79%
Debt Paid & Issued, Net	$48.23M		$87.55M
YoY Change	-44.91%		41195.75%
Cash From Financing Activities	-$24.77M	-12.80M	-4.062M
YoY Change	509.82%	12.28%	-110.57%
NET CHANGE
Cash From Operating Activities	$173.6M	48.70M	163.4M
Cash From Investing Activities	-$132.6M	-35.90M	-159.3M
Cash From Financing Activities	-$24.77M	-12.80M	-4.062M
Net Change In Cash	$16.22M	0.000000001863	0.000
YoY Change		-100.0%
FREE CASH FLOW
Cash From Operating Activities	$173.6M	$48.70M	$163.4M
Capital Expenditures	-$132.9M	-$35.40M	-$161.3M
Free Cash Flow	$306.5M	$84.10M	$324.7M
YoY Change	-5.61%	-8.69%	16.94%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value
CY2017	dei	Amendment Flag AmendmentFlag	false
CY2017	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2017	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2017
CY2017	dei	Document Period End Date DocumentPeriodEndDate	2017-12-31
CY2017	dei	Document Type DocumentType	10-K
CY2017Q2	dei	Entity Public Float EntityPublicFloat	1500154049
CY2017Q4	ottr	Accounts Payable Outstanding Related To Capital Additions AccountsPayableOutstandingRelatedToCapitalAdditions	13887000
CY2016Q4	ottr	Accounts Payable Outstanding Related To Capital Additions AccountsPayableOutstandingRelatedToCapitalAdditions	13533000
CY2015	ottr	Adjustment Income Loss From Discontinued Operations Net Of Tax AdjustmentIncomeLossFromDiscontinuedOperationsNetOfTax	-6404000
CY2017	ottr	Adjustment Income Loss From Discontinued Operations Net Of Tax AdjustmentIncomeLossFromDiscontinuedOperationsNetOfTax	320000
CY2016	ottr	Adjustment Income Loss From Discontinued Operations Net Of Tax AdjustmentIncomeLossFromDiscontinuedOperationsNetOfTax	284000
CY2017	ottr	Asset Retirement Obligation Gain On Settlement AssetRetirementObligationGainOnSettlement
CY2016	ottr	Asset Retirement Obligation Gain On Settlement AssetRetirementObligationGainOnSettlement
CY2017	ottr	Asset Retirement Obligation Settlements Accumulated Depreciation AssetRetirementObligationSettlementsAccumulatedDepreciation
CY2016	ottr	Asset Retirement Obligation Settlements Accumulated Depreciation AssetRetirementObligationSettlementsAccumulatedDepreciation
CY2017	ottr	Asset Retirement Obligation Settlements Asset Retirement Obligation AssetRetirementObligationSettlementsAssetRetirementObligation
CY2016	ottr	Asset Retirement Obligation Settlements Asset Retirement Obligation AssetRetirementObligationSettlementsAssetRetirementObligation
CY2017	ottr	Asset Retirement Obligation Settlements Retired Original Capitalized Asset Retirement Cost AssetRetirementObligationSettlementsRetiredOriginalCapitalizedAssetRetirementCost
CY2016	ottr	Asset Retirement Obligation Settlements Retired Original Capitalized Asset Retirement Cost AssetRetirementObligationSettlementsRetiredOriginalCapitalizedAssetRetirementCost
CY2017	ottr	Asset Retirement Obligation Settlements Settlement Cost AssetRetirementObligationSettlementsSettlementCost
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CY2016	ottr	Asset Retirement Obligation Settlements Settlement Cost AssetRetirementObligationSettlementsSettlementCost
CY2017Q4	ottr	Deferred Tax Assets Production Tax Credits DeferredTaxAssetsProductionTaxCredits	40614000
CY2016Q4	ottr	Deferred Tax Assets Production Tax Credits DeferredTaxAssetsProductionTaxCredits	43433000
CY2016Q4	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation CapitalizedCostsAssetRetirementCostsAccumulatedDepreciation	795000
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CY2017Q4	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation CapitalizedCostsAssetRetirementCostsAccumulatedDepreciation	915000
CY2017	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Depreciation Expense CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationDepreciationExpense	120000
CY2016	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Depreciation Expense CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationDepreciationExpense	122000
CY2017	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Liabilities Incurred CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationLiabilitiesIncurred
CY2016	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Liabilities Incurred CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationLiabilitiesIncurred
CY2017	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Liabilities Settled CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationLiabilitiesSettled
CY2016	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Liabilities Settled CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationLiabilitiesSettled
CY2017	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Revision Of Estimate CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationRevisionOfEstimate
CY2016	ottr	Capitalized Costs Asset Retirement Costs Accumulated Depreciation Revision Of Estimate CapitalizedCostsAssetRetirementCostsAccumulatedDepreciationRevisionOfEstimate
CY2017	ottr	Capitalized Costs Asset Retirement Costs Liabilities Incurred CapitalizedCostsAssetRetirementCostsLiabilitiesIncurred
CY2016	ottr	Capitalized Costs Asset Retirement Costs Liabilities Incurred CapitalizedCostsAssetRetirementCostsLiabilitiesIncurred
CY2017	ottr	Capitalized Costs Asset Retirement Costs Liabilities Settled CapitalizedCostsAssetRetirementCostsLiabilitiesSettled
CY2016	ottr	Capitalized Costs Asset Retirement Costs Liabilities Settled CapitalizedCostsAssetRetirementCostsLiabilitiesSettled
CY2017	ottr	Capitalized Costs Asset Retirement Costs Revision Of Estimate CapitalizedCostsAssetRetirementCostsRevisionOfEstimate
CY2016	ottr	Capitalized Costs Asset Retirement Costs Revision Of Estimate CapitalizedCostsAssetRetirementCostsRevisionOfEstimate	-103000
CY2017	ottr	Change In Checks Written In Excess Of Cash ChangeInChecksWrittenInExcessOfCash	-2434000
CY2016	ottr	Change In Checks Written In Excess Of Cash ChangeInChecksWrittenInExcessOfCash	3363000
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CY2017Q4	ottr	Deferred Tax Assets Cost Of Removal DeferredTaxAssetsCostOfRemoval	21800000
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CY2017Q4	ottr	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Pension And Postretirement Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensionAndPostretirementBenefits	31894000
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CY2017Q4	ottr	Deferred Tax Liabilities Operating Loss Carryforwards State And Local DeferredTaxLiabilitiesOperatingLossCarryforwardsStateAndLocal	673000
CY2016Q4	ottr	Deferred Tax Liabilities Operating Loss Carryforwards State And Local DeferredTaxLiabilitiesOperatingLossCarryforwardsStateAndLocal	1352000
CY2017Q4	ottr	Deferred Tax Liabilities Retirement Benefits Regulatory Asset DeferredTaxLiabilitiesRetirementBenefitsRegulatoryAsset	31894000
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CY2017Q4	ottr	Deferred Tax Liabilities Tax Credits DeferredTaxLiabilitiesTaxCredits	4112000
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CY2017	ottr	Deferred Tax Liabilities Tax Effect On Deferred Tax Valuation Adjustment DeferredTaxLiabilitiesTaxEffectOnDeferredTaxValuationAdjustment	38786000
CY2017	ottr	Deferred Tax Liability Change Due To Accruals And Amortizations DeferredTaxLiabilityChangeDueToAccrualsAndAmortizations	20012000
CY2017	ottr	Deferred Tax Liability Deferred Tax Valuation Adjustment DeferredTaxLiabilityDeferredTaxValuationAdjustment	109072000
CY2017	ottr	Directors Deferred Compensation DirectorsDeferredCompensation	560
CY2017	ottr	Discontinued Operation Adjusted Tax Effect Of Discontinued Operation DiscontinuedOperationAdjustedTaxEffectOfDiscontinuedOperation	213000
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CY2017	ottr	Discontinued Operation Impairment Loss Net Of Income Tax Benefit DiscontinuedOperationImpairmentLossNetOfIncomeTaxBenefit
CY2016	ottr	Discontinued Operation Impairment Loss Net Of Income Tax Benefit DiscontinuedOperationImpairmentLossNetOfIncomeTaxBenefit
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CY2017	ottr	Discontinued Operation Tax Expense Benefit From Provision For Gain Loss On Impairment DiscontinuedOperationTaxExpenseBenefitFromProvisionForGainLossOnImpairment	0
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CY2015	ottr	Disposal Group Including Discontinued Operation Other Income Expense DisposalGroupIncludingDiscontinuedOperationOtherIncomeExpense	69000
CY2017	ottr	Effective Income Tax Rate Reconciliation Corporate Owned Life Insurance Amount EffectiveIncomeTaxRateReconciliationCorporateOwnedLifeInsuranceAmount	-845000
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CY2017	ottr	Effective Income Tax Rate Reconciliation Deduction Equity Method Stock Awards EffectiveIncomeTaxRateReconciliationDeductionEquityMethodStockAwards	751000
CY2016	ottr	Effective Income Tax Rate Reconciliation Deduction Equity Method Stock Awards EffectiveIncomeTaxRateReconciliationDeductionEquityMethodStockAwards
CY2015	ottr	Effective Income Tax Rate Reconciliation Deduction Equity Method Stock Awards EffectiveIncomeTaxRateReconciliationDeductionEquityMethodStockAwards
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CY2015	ottr	Income Loss Before Income Tax IncomeLossBeforeIncomeTax	83978000
CY2017	ottr	Income Tax Benefit Expense Continuing And Discontinued Operations IncomeTaxBenefitExpenseContinuingAndDiscontinuedOperations	27256000
CY2016	ottr	Income Tax Benefit Expense Continuing And Discontinued Operations IncomeTaxBenefitExpenseContinuingAndDiscontinuedOperations	20219000
CY2015	ottr	Income Tax Benefit Expense Continuing And Discontinued Operations IncomeTaxBenefitExpenseContinuingAndDiscontinuedOperations	24633000
CY2017	ottr	Income Tax Reconciliation Allowance For Funds Used During Construction IncomeTaxReconciliationAllowanceForFundsUsedDuringConstruction	322000
CY2016	ottr	Income Tax Reconciliation Allowance For Funds Used During Construction IncomeTaxReconciliationAllowanceForFundsUsedDuringConstruction	280000
CY2015	ottr	Income Tax Reconciliation Allowance For Funds Used During Construction IncomeTaxReconciliationAllowanceForFundsUsedDuringConstruction	426000
CY2017	ottr	Income Tax Reconciliation Differences Reversing In Excess Of Federal Rates IncomeTaxReconciliationDifferencesReversingInExcessOfFederalRates	551000
CY2016	ottr	Income Tax Reconciliation Differences Reversing In Excess Of Federal Rates IncomeTaxReconciliationDifferencesReversingInExcessOfFederalRates	77000
CY2015	ottr	Income Tax Reconciliation Differences Reversing In Excess Of Federal Rates IncomeTaxReconciliationDifferencesReversingInExcessOfFederalRates	-1143000
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CY2017	ottr	Increase Decrease In Deferred Charges And Other Assets IncreaseDecreaseInDeferredChargesAndOtherAssets	-2173000
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CY2015	ottr	Increase Decrease In Deferred Charges And Other Assets IncreaseDecreaseInDeferredChargesAndOtherAssets	11407000
CY2017	ottr	Increase Decrease In Interest Payable And Income Taxes Receivable Payable Net IncreaseDecreaseInInterestPayableAndIncomeTaxesReceivablePayableNet	-1186000
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CY2015	ottr	Increase Decrease In Interest Payable And Income Taxes Receivable Payable Net IncreaseDecreaseInInterestPayableAndIncomeTaxesReceivablePayableNet	-3943000
CY2017	ottr	Increase Decrease In Other Operating Liabilities And Increase Decrease In Deferred Liabilities IncreaseDecreaseInOtherOperatingLiabilitiesAndIncreaseDecreaseInDeferredLiabilities	-19257000
CY2016	ottr	Increase Decrease In Other Operating Liabilities And Increase Decrease In Deferred Liabilities IncreaseDecreaseInOtherOperatingLiabilitiesAndIncreaseDecreaseInDeferredLiabilities	-14685000
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CY2017	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Nonvested Restricted Shares IncrementalCommonSharesAttributableToDilutiveEffectOfNonvestedRestrictedShares	20380
CY2016	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Nonvested Restricted Shares IncrementalCommonSharesAttributableToDilutiveEffectOfNonvestedRestrictedShares	16778
CY2015	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Nonvested Restricted Shares IncrementalCommonSharesAttributableToDilutiveEffectOfNonvestedRestrictedShares	22848
CY2017	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Shares Expected To Be Issued Under Deferred Compensation Program For Directors IncrementalCommonSharesAttributableToDilutiveEffectOfSharesExpectedToBeIssuedUnderDeferredCompensationProgramForDirectors	2970
CY2016	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Shares Expected To Be Issued Under Deferred Compensation Program For Directors IncrementalCommonSharesAttributableToDilutiveEffectOfSharesExpectedToBeIssuedUnderDeferredCompensationProgramForDirectors	3417
CY2015	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Shares Expected To Be Issued Under Deferred Compensation Program For Directors IncrementalCommonSharesAttributableToDilutiveEffectOfSharesExpectedToBeIssuedUnderDeferredCompensationProgramForDirectors	13488
CY2017	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Underlying Shares Related To Nonvested Restricted Stock Units Granted To Employees IncrementalCommonSharesAttributableToDilutiveEffectOfUnderlyingSharesRelatedToNonvestedRestrictedStockUnitsGrantedToEmployees	56952
CY2016	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Underlying Shares Related To Nonvested Restricted Stock Units Granted To Employees IncrementalCommonSharesAttributableToDilutiveEffectOfUnderlyingSharesRelatedToNonvestedRestrictedStockUnitsGrantedToEmployees	45712
CY2015	ottr	Incremental Common Shares Attributable To Dilutive Effect Of Underlying Shares Related To Nonvested Restricted Stock Units Granted To Employees IncrementalCommonSharesAttributableToDilutiveEffectOfUnderlyingSharesRelatedToNonvestedRestrictedStockUnitsGrantedToEmployees	36180
	ottr	Interest On Refundable Amount Interim Revenue Portion InterestOnRefundableAmountInterimRevenuePortion	265000
	ottr	Interim Period Accrued Refund InterimPeriodAccruedRefund	8779000
	ottr	Interim Revenue Earned And Reported Net InterimRevenueEarnedAndReportedNet	14510000
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CY2017Q4	ottr	Line Of Credit Facility Amount Restricted LineOfCreditFacilityAmountRestricted	300000
CY2017	ottr	Maximum Per Share Differences Between Basic And Diluted Earnings Per Share In Total Or From Continuing Or Discontinued Operations MaximumPerShareDifferencesBetweenBasicAndDilutedEarningsPerShareInTotalOrFromContinuingOrDiscontinuedOperations	0.014
CY2016	ottr	Maximum Per Share Differences Between Basic And Diluted Earnings Per Share In Total Or From Continuing Or Discontinued Operations MaximumPerShareDifferencesBetweenBasicAndDilutedEarningsPerShareInTotalOrFromContinuingOrDiscontinuedOperations	0.014
CY2015	ottr	Maximum Per Share Differences Between Basic And Diluted Earnings Per Share In Total Or From Continuing Or Discontinued Operations MaximumPerShareDifferencesBetweenBasicAndDilutedEarningsPerShareInTotalOrFromContinuingOrDiscontinuedOperations	0.014
CY2017Q4	ottr	Net Regulatory Assets Liability Current NetRegulatoryAssetsLiabilityCurrent	12863000
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CY2017	ottr	Payments Of Ordinary Dividends And Other Distributions PaymentsOfOrdinaryDividendsAndOtherDistributions	50632000
CY2016	ottr	Payments Of Ordinary Dividends And Other Distributions PaymentsOfOrdinaryDividendsAndOtherDistributions	48244000
CY2015	ottr	Payments Of Ordinary Dividends And Other Distributions PaymentsOfOrdinaryDividendsAndOtherDistributions	46223000
CY2017	ottr	Period For Unrecognized Tax Benefits Not Expected Change PeriodForUnrecognizedTaxBenefitsNotExpectedChange	P1Y
CY2017	ottr	Property Taxes Electric Utility Operations PropertyTaxesElectricUtilityOperations	15053000
CY2016	ottr	Property Taxes Electric Utility Operations PropertyTaxesElectricUtilityOperations	14266000
CY2015	ottr	Property Taxes Electric Utility Operations PropertyTaxesElectricUtilityOperations	13512000
CY2017Q4	ottr	Public Utilities Final Projected Debt Capital Structure Percentage PublicUtilitiesFinalProjectedDebtCapitalStructurePercentage	0.475
CY2017Q4	ottr	Public Utilities Final Projected Equity Capital Structure Percentage PublicUtilitiesFinalProjectedEquityCapitalStructurePercentage	0.525
CY2017Q4	ottr	Public Utilities Final Projected Jurisdictional Rate Amount PublicUtilitiesFinalProjectedJurisdictionalRateAmount	471000000
CY2017Q4	ottr	Public Utilities Final Projected Rate Percentage PublicUtilitiesFinalProjectedRatePercentage	0.0534
CY2017Q4	ottr	Public Utilities Final Projected Return On Equity Percentage PublicUtilitiesFinalProjectedReturnOnEquityPercentage	0.0941
CY2017Q4	ottr	Public Utilities Final Projected Return On Rate Base Percentage PublicUtilitiesFinalProjectedReturnOnRateBasePercentage	0.075056
CY2016Q2	ottr	Public Utilities Interim Debt Capital Structure Percentage PublicUtilitiesInterimDebtCapitalStructurePercentage	0.475
CY2016Q2	ottr	Public Utilities Interim Equity Capital Structure Percentage PublicUtilitiesInterimEquityCapitalStructurePercentage	0.525
CY2016Q2	ottr	Public Utilities Interim Jurisdictional Rate Amount PublicUtilitiesInterimJurisdictionalRateAmount	483000000
CY2016Q2	ottr	Public Utilities Interim Rate Amount PublicUtilitiesInterimRateAmount	16816000
CY2016Q2	ottr	Public Utilities Interim Rate Percentage PublicUtilitiesInterimRatePercentage	0.0956
CY2016Q2	ottr	Public Utilities Interim Return On Equity Percentage PublicUtilitiesInterimReturnOnEquityPercentage	0.104
CY2016Q2	ottr	Public Utilities Interim Return On Rate Base Percentage PublicUtilitiesInterimReturnOnRateBasePercentage	0.0807
CY2017Q4	ottr	Public Utilities Projected Final Rate Amount PublicUtilitiesProjectedFinalRateAmount	10471000
CY2017Q4	ottr	Public Utilities Property Plant And Equipment Electric PublicUtilitiesPropertyPlantAndEquipmentElectric	1981018000
CY2016Q4	ottr	Public Utilities Property Plant And Equipment Electric PublicUtilitiesPropertyPlantAndEquipmentElectric	1860357000
CY2017	ottr	Restricted Stock Issued To Directors RestrictedStockIssuedToDirectors	17600
CY2017	ottr	Shares Withheld For Individual Income Tax Requirements SharesWithheldForIndividualIncomeTaxRequirements	47704
CY2017	ottr	Standard Product Warranty Term StandardProductWarrantyTerm	P1Y
CY2017	ottr	Stock Issued During Period Shares For Cash Invested StockIssuedDuringPeriodSharesForCashInvested	29463
CY2017	ottr	Stock Issued During Period Shares For Cash Invested Under Employee Stock Purchase Plan StockIssuedDuringPeriodSharesForCashInvestedUnderEmployeeStockPurchasePlan	5284
CY2017	ottr	Stock Issued During Period Shares For Dividend Reinvestments StockIssuedDuringPeriodSharesForDividendReinvestments	68235
CY2017	ottr	Stock Issued During Period Shares For Dividend Reinvestments Under Employee Stock Purchase Plan StockIssuedDuringPeriodSharesForDividendReinvestmentsUnderEmployeeStockPurchasePlan	9566
CY2017	ottr	Stock Issued During Period Shares Vesting Of Restricted Stock Units StockIssuedDuringPeriodSharesVestingOfRestrictedStockUnits	22225
CY2017	ottr	Stock Performance Awards Issued To Executives StockPerformanceAwardsIssuedToExecutives	89291
CY2017	ottr	Wind Tax Credits Amortization Period WindTaxCreditsAmortizationPeriod	P25Y
CY2017Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	84185000
CY2016Q4	us-gaap	Accounts Payable Current AccountsPayableCurrent	89350000
CY2017Q4	us-gaap	Accounts Payable Related Parties Current AccountsPayableRelatedPartiesCurrent	6000
CY2016Q4	us-gaap	Accounts Payable Related Parties Current AccountsPayableRelatedPartiesCurrent	5958000
CY2017Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	68466000
CY2016Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	68242000
CY2017Q4	us-gaap	Accounts Receivable Related Parties Current AccountsReceivableRelatedPartiesCurrent	2098000
CY2016Q4	us-gaap	Accounts Receivable Related Parties Current AccountsReceivableRelatedPartiesCurrent	1706000
CY2017Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	16808000
CY2016Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	16000000
CY2017Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	21379000
CY2016Q4	us-gaap	Accumulated Deferred Investment Tax Credit AccumulatedDeferredInvestmentTaxCredit	22849000
CY2017Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	799419000
CY2016Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	748219000
CY2017Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-5631000
CY2016Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-3800000
CY2017Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	343450000
CY2016Q4	us-gaap	Additional Paid In Capital Common Stock AdditionalPaidInCapitalCommonStock	337684000
CY2015	us-gaap	Adjustment To Additional Paid In Capital Income Tax Effect From Share Based Compensation Net AdjustmentToAdditionalPaidInCapitalIncomeTaxEffectFromShareBasedCompensationNet	82000
CY2015	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	1716000
CY2016	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3178000
CY2017	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	3642000
CY2017Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1094000
CY2016Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	1262000
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1347000
CY2016	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1436000
CY2015	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	1127000
CY2016Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	8341000
CY2015Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	8084000
CY2017Q4	us-gaap	Asset Retirement Obligation AssetRetirementObligation	8719000
CY2017	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	378000
CY2016	us-gaap	Asset Retirement Obligation Accretion Expense AssetRetirementObligationAccretionExpense	360000
CY2017	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred
CY2016	us-gaap	Asset Retirement Obligation Liabilities Incurred AssetRetirementObligationLiabilitiesIncurred
CY2017	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled
CY2016	us-gaap	Asset Retirement Obligation Liabilities Settled AssetRetirementObligationLiabilitiesSettled
CY2017	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate
CY2016	us-gaap	Asset Retirement Obligation Revision Of Estimate AssetRetirementObligationRevisionOfEstimate	-103000
CY2017Q4	us-gaap	Assets Assets	2004278000
CY2016Q4	us-gaap	Assets Assets	1912385000
CY2015Q4	us-gaap	Assets Assets	1818683000
CY2017Q4	us-gaap	Assets Current AssetsCurrent	239127000
CY2016Q4	us-gaap	Assets Current AssetsCurrent	208015000
CY2017Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1187272000
CY2016Q4	us-gaap	Capitalization Longterm Debt And Equity CapitalizationLongtermDebtAndEquity	1175445000
CY2017	us-gaap	Capitalized Computer Software Additions CapitalizedComputerSoftwareAdditions	154000
CY2016Q4	us-gaap	Capitalized Costs Asset Retirement Costs CapitalizedCostsAssetRetirementCosts	2983000
CY2015Q4	us-gaap	Capitalized Costs Asset Retirement Costs CapitalizedCostsAssetRetirementCosts	3086000
CY2017Q4	us-gaap	Capitalized Costs Asset Retirement Costs CapitalizedCostsAssetRetirementCosts	2983000
CY2016Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue
CY2015Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue
CY2014Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue
CY2017Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	16216000
CY2017	us-gaap	Cash And Cash Equivalents Period Increase Decrease CashAndCashEquivalentsPeriodIncreaseDecrease	16216000
CY2017	us-gaap	Cash Dividends Paid To Parent Company CashDividendsPaidToParentCompany	50571000
CY2016	us-gaap	Cash Dividends Paid To Parent Company CashDividendsPaidToParentCompany	77779000
CY2015	us-gaap	Cash Dividends Paid To Parent Company CashDividendsPaidToParentCompany	46188000
CY2015	us-gaap	Cash Provided By Used In Financing Activities Discontinued Operations CashProvidedByUsedInFinancingActivitiesDiscontinuedOperations	316000
CY2015	us-gaap	Cash Provided By Used In Investing Activities Discontinued Operations CashProvidedByUsedInInvestingActivitiesDiscontinuedOperations	-1769000
CY2017	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-26000
CY2016	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-155000
CY2015	us-gaap	Cash Provided By Used In Operating Activities Discontinued Operations CashProvidedByUsedInOperatingActivitiesDiscontinuedOperations	-14000000
CY2017Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies
CY2016Q4	us-gaap	Commitments And Contingencies CommitmentsAndContingencies
CY2017	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.28
CY2016	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.25
CY2015	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.23
CY2017Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5
CY2016Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	5
CY2017Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000
CY2016Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000
CY2017Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	39557491
CY2016Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	39348136
CY2017Q4	us-gaap	Common Stock Value CommonStockValue	197787000
CY2016Q4	us-gaap	Common Stock Value CommonStockValue	196741000
CY2017	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	70608000
CY2016	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	62419000
CY2015	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	60110000
CY2017Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	141067000
CY2016Q4	us-gaap	Construction In Progress Gross ConstructionInProgressGross	153261000
CY2017	us-gaap	Cost Of Goods Sold Excluding Depreciation Depletion And Amortization CostOfGoodsSoldExcludingDepreciationDepletionAndAmortization	316562000
CY2016	us-gaap	Cost Of Goods Sold Excluding Depreciation Depletion And Amortization CostOfGoodsSoldExcludingDepreciationDepletionAndAmortization	295222000
CY2015	us-gaap	Cost Of Goods Sold Excluding Depreciation Depletion And Amortization CostOfGoodsSoldExcludingDepreciationDepletionAndAmortization	295032000
CY2017	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	64807000
CY2016	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	63226000
CY2015	us-gaap	Cost Of Purchased Power CostOfPurchasedPower	78150000
CY2017	us-gaap	Costs And Expenses CostsAndExpenses	723216000
CY2016	us-gaap	Costs And Expenses CostsAndExpenses	692440000
CY2015	us-gaap	Costs And Expenses CostsAndExpenses	670590000
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	4581000
CY2016	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	1070000
CY2015	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	211000
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1154000
CY2016	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1211000
CY2015	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	1000
CY2017Q4	us-gaap	Debt Instrument Interest Rate Stated Percentage DebtInstrumentInterestRateStatedPercentage	0.0254
CY2016Q4	us-gaap	Debt Instrument Interest Rate Stated Percentage DebtInstrumentInterestRateStatedPercentage	0.0254
CY2017	us-gaap	Debt Instrument Maturity Date DebtInstrumentMaturityDate	2021-03-18
CY2016	us-gaap	Debt Instrument Maturity Date DebtInstrumentMaturityDate	2021-03-18
CY2017Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2145000
CY2016Q4	us-gaap	Debt Instrument Unamortized Discount DebtInstrumentUnamortizedDiscount	2400000
CY2017Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	602937000
CY2016Q4	us-gaap	Debt Longterm And Shortterm Combined Amount DebtLongtermAndShorttermCombinedAmount	581425000
CY2017	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	25320000
CY2016	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	23586000
CY2015	us-gaap	Deferred Federal Income Tax Expense Benefit DeferredFederalIncomeTaxExpenseBenefit	23050000
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	24001000
CY2016	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	19124000
CY2015	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	26027000
CY2017Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	312293000
CY2016Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	442470000
CY2017Q4	us-gaap	Deferred Revenue And Credits Noncurrent DeferredRevenueAndCreditsNoncurrent	358102000
CY2016Q4	us-gaap	Deferred Revenue And Credits Noncurrent DeferredRevenueAndCreditsNoncurrent	339365000
CY2017	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	4529000
CY2016	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	2589000
CY2015	us-gaap	Deferred State And Local Income Tax Expense Benefit DeferredStateAndLocalIncomeTaxExpenseBenefit	6763000
CY2017Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	211792000
CY2016Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	215879000
CY2017Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	3203000
CY2016Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	3865000
CY2017Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	668000
CY2016Q4	us-gaap	Deferred Tax Assets Other DeferredTaxAssetsOther	5371000
CY2017Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	6499000
CY2016Q4	us-gaap	Deferred Tax Assets Property Plant And Equipment DeferredTaxAssetsPropertyPlantAndEquipment	9876000
CY2017Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	39465000
CY2016Q4	us-gaap	Deferred Tax Assets Regulatory Assets And Liabilities DeferredTaxAssetsRegulatoryAssetsAndLiabilities	2422000
CY2017Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Other DeferredTaxAssetsTaxCreditCarryforwardsOther	32962000
CY2016Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Other DeferredTaxAssetsTaxCreditCarryforwardsOther	32962000
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Compensated Absences DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsCompensatedAbsences	1844000
CY2016Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Compensated Absences DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsCompensatedAbsences	2725000
CY2017Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	32328000
CY2016Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Compensation And Benefits Employee Benefits DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBenefits	44381000
CY2017Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	100501000
CY2016Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	226591000
CY2017Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	100501000
CY2016Q4	us-gaap	Deferred Tax Liabilities Noncurrent DeferredTaxLiabilitiesNoncurrent	226591000
CY2016Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	17497000
CY2017Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	4000000
CY2017	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P2Y
CY2017	us-gaap	Employee Stock Ownership Plan Esop Cash Contributions To Esop EmployeeStockOwnershipPlanESOPCashContributionsToESOP	612000
CY2016	us-gaap	Employee Stock Ownership Plan Esop Cash Contributions To Esop EmployeeStockOwnershipPlanESOPCashContributionsToESOP	647000
CY2015	us-gaap	Employee Stock Ownership Plan Esop Cash Contributions To Esop EmployeeStockOwnershipPlanESOPCashContributionsToESOP	674000
CY2015	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Net Of Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax	-5404000
CY2017	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	213000
CY2017Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	3631000
CY2016Q4	us-gaap	Deferred Tax Liabilities Other DeferredTaxLiabilitiesOther	11804000
CY2017Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	257906000
CY2016Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	371761000
CY2017Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	109708000
CY2016Q4	us-gaap	Defined Benefit Pension Plan Liabilities Noncurrent DefinedBenefitPensionPlanLiabilitiesNoncurrent	97627000
CY2017	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	4211000
CY2016	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	3877000
CY2015	us-gaap	Defined Contribution Plan Cost Recognized DefinedContributionPlanCostRecognized	3602000
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	72545000
CY2016	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	73445000
CY2015	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	60363000
CY2015	us-gaap	Discontinued Operation Gain Loss From Disposal Of Discontinued Operation Before Income Tax DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax	11690000
CY2015	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	7160000
CY2017	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
CY2016	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
CY2017	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Net Of Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax	320000
CY2016	us-gaap	Discontinued Operation Income Loss From Discontinued Operation During Phase Out Period Net Of Tax DiscontinuedOperationIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriodNetOfTax	284000
CY2016	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	138000
CY2015	us-gaap	Discontinued Operation Tax Effect Of Discontinued Operation DiscontinuedOperationTaxEffectOfDiscontinuedOperation	2991000
CY2017	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	213000
CY2016	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	138000
CY2015	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Discontinued Operation During Phase Out Period DiscontinuedOperationTaxEffectOfIncomeLossFromDiscontinuedOperationDuringPhaseOutPeriod	-1539000
CY2017	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	0
CY2016	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	0
CY2015	us-gaap	Discontinued Operation Tax Effect Of Income Loss From Disposal Of Discontinued Operation DiscontinuedOperationTaxEffectOfIncomeLossFromDisposalOfDiscontinuedOperation	4530000
CY2015	us-gaap	Disposal Group Including Discontinued Operation Interest Expense DisposalGroupIncludingDiscontinuedOperationInterestExpense
CY2017	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	-533000
CY2016	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	-422000
CY2015	us-gaap	Disposal Group Including Discontinued Operation Operating Expense DisposalGroupIncludingDiscontinuedOperationOperatingExpense	31635000
CY2015	us-gaap	Disposal Group Including Discontinued Operation Revenue DisposalGroupIncludingDiscontinuedOperationRevenue	24623000
CY2015	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	46223000
CY2016	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	48244000
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	50632000
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.84
CY2016	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.62
CY2015	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.58
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.82
CY2016	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.61
CY2015	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.58
CY2017	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.273
CY2016	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.245
CY2015	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.293
CY2017	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2016	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2015	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.35
CY2017	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	434506000
CY2016	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	427349000
CY2015	us-gaap	Electric Utility Revenue ElectricUtilityRevenue	407039000
CY2017Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	21534000
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	163386000
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	117540000
CY2017	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-2667000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	9470000
CY2016Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	8123000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Next Twelve Months FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths	1315000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	1099000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	1099000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	1133000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	1184000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	23235000
CY2016Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	23081000
CY2017Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	13765000
CY2016Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	14958000
CY2016Q4	us-gaap	Goodwill Goodwill	37572000
CY2017Q4	us-gaap	Goodwill Goodwill	37572000
CY2015Q4	us-gaap	Goodwill Goodwill	39732000
CY2016Q4	us-gaap	Goodwill Gross GoodwillGross	37572000
CY2015Q4	us-gaap	Goodwill Gross GoodwillGross	39732000
CY2016Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss
CY2015Q4	us-gaap	Goodwill Impaired Accumulated Impairment Loss GoodwillImpairedAccumulatedImpairmentLoss
CY2017	us-gaap	Goodwill Period Increase Decrease GoodwillPeriodIncreaseDecrease
CY2016	us-gaap	Goodwill Period Increase Decrease GoodwillPeriodIncreaseDecrease	-2160000
CY2015	us-gaap	Impairment Of Long Lived Assets To Be Disposed Of ImpairmentOfLongLivedAssetsToBeDisposedOf	1000000
CY2017	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	72119000
CY2016	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	62037000
CY2015	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	58589000
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	99162000
CY2016	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	82118000
CY2015	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	80231000
CY2017	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.83
CY2016	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.61
CY2015	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.56
CY2017	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.81
CY2016	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.60
CY2015	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.56
CY2017	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	320000
CY2016	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	284000
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax IncomeLossFromDiscontinuedOperationsNetOfTax	756000
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	173603000
CY2016	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	163541000
CY2015	us-gaap	Net Cash Provided By Used In Operating Activities Continuing Operations NetCashProvidedByUsedInOperatingActivitiesContinuingOperations	131540000
CY2017	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.01
CY2016	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.01
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	0.02
CY2017	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.01
CY2016	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.01
CY2015	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.02
CY2017	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-1470000
CY2016	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-1657000
CY2015	us-gaap	Income Tax Credits And Adjustments IncomeTaxCreditsAndAdjustments	-1878000
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	27043000
CY2016	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	20081000
CY2015	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	21642000
CY2017	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	1756000
CY2016	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability
CY2015	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability
CY2017	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	509000
CY2016	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	537000
CY2015	us-gaap	Income Tax Rate Reconciliation Deductions Employee Stock Ownership Plan Dividends IncomeTaxRateReconciliationDeductionsEmployeeStockOwnershipPlanDividends	560000
CY2017	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities	1471000
CY2016	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities	482000
CY2015	us-gaap	Income Tax Reconciliation Deductions Qualified Production Activities IncomeTaxReconciliationDeductionsQualifiedProductionActivities
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	34707000
CY2016	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	28741000
CY2015	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	28081000
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	-1873000
CY2016	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	-1231000
CY2015	us-gaap	Income Tax Reconciliation Nondeductible Expense IncomeTaxReconciliationNondeductibleExpense	-705000
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4341000
CY2016	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	2848000
CY2015	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	4945000
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	164000
CY2016	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	350000
CY2015	us-gaap	Income Tax Reconciliation Tax Credits Investment IncomeTaxReconciliationTaxCreditsInvestment	571000
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	850000
CY2016	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	850000
CY2015	us-gaap	Income Tax Reconciliation Tax Credits Other IncomeTaxReconciliationTaxCreditsOther	850000
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	5064000
CY2016	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	-1291000
CY2015	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	7322000
CY2017Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	1181000
CY2016Q4	us-gaap	Income Taxes Receivable IncomeTaxesReceivable	662000
CY2016	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	11941000
CY2015	us-gaap	Increase Decrease In Accounts Payable And Accrued Liabilities IncreaseDecreaseInAccountsPayableAndAccruedLiabilities	-15150000
CY2017	us-gaap	Increase Decrease In Allowance For Equity Funds Used During Construction IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction	986000
CY2016	us-gaap	Increase Decrease In Allowance For Equity Funds Used During Construction IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction	857000
CY2015	us-gaap	Increase Decrease In Allowance For Equity Funds Used During Construction IncreaseDecreaseInAllowanceForEquityFundsUsedDuringConstruction	1303000
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	4294000
CY2016	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-1874000
CY2015	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-1960000
CY2017	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	3060000
CY2016	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	2541000
CY2015	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	210000
CY2017	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	2135000
CY2016	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	944000
CY2015	us-gaap	Increase Decrease In Receivables IncreaseDecreaseInReceivables	1746000
CY2017	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants
CY2016	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants
CY2015	us-gaap	Incremental Common Shares Attributable To Call Options And Warrants IncrementalCommonSharesAttributableToCallOptionsAndWarrants	330
CY2017	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	210784
CY2016	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	118644
CY2015	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	100194
CY2017Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	13765000
CY2016Q4	us-gaap	Intangible Assets Net Excluding Goodwill IntangibleAssetsNetExcludingGoodwill	14958000
CY2017	us-gaap	Interest And Debt Expense InterestAndDebtExpense	29604000
CY2016	us-gaap	Interest And Debt Expense InterestAndDebtExpense	31886000
CY2015	us-gaap	Interest And Debt Expense InterestAndDebtExpense	31160000
CY2017	us-gaap	Interest Paid Net InterestPaidNet	29791000
CY2016	us-gaap	Interest Paid Net InterestPaidNet	31269000
CY2015	us-gaap	Interest Paid Net InterestPaidNet	30512000
CY2017Q4	us-gaap	Interest Receivable Current InterestReceivableCurrent	117000
CY2016Q4	us-gaap	Interest Receivable Current InterestReceivableCurrent	141000
CY2017Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	26605000
CY2016Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	27755000
CY2017Q4	us-gaap	Inventory Net InventoryNet	88034000
CY2016Q4	us-gaap	Inventory Net InventoryNet	83740000
CY2017Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	47207000
CY2016Q4	us-gaap	Inventory Raw Materials And Supplies InventoryRawMaterialsAndSupplies	44231000
CY2017Q4	us-gaap	Inventory Work In Process InventoryWorkInProcess	14222000
CY2016Q4	us-gaap	Inventory Work In Process InventoryWorkInProcess	11754000
CY2017Q4	us-gaap	Investments Investments	8629000
CY2016Q4	us-gaap	Investments Investments	8417000
CY2017Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	2004278000
CY2016Q4	us-gaap	Liabilities And Stockholders Equity LiabilitiesAndStockholdersEquity	1912385000
CY2017Q4	us-gaap	Liabilities Current LiabilitiesCurrent	256653000
CY2016Q4	us-gaap	Liabilities Current LiabilitiesCurrent	215671000
CY2017Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation	492000
CY2016Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation	1363000
CY2017Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	492000
CY2016Q4	us-gaap	Liabilities Of Disposal Group Including Discontinued Operation Current LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent	1363000
CY2017Q4	us-gaap	Line Of Credit LineOfCredit	112371000
CY2017Q4	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	300000000
CY2017Q4	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	187329000
CY2016Q4	us-gaap	Line Of Credit Facility Remaining Borrowing Capacity LineOfCreditFacilityRemainingBorrowingCapacity	257067000
CY2017Q4	us-gaap	Long Term Debt LongTermDebt	492711000
CY2016Q4	us-gaap	Long Term Debt LongTermDebt	540942000
CY2017Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	186000
CY2016Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	33201000
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	186000
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	30000000
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	140167000
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	185000
CY2017Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	172000
CY2017Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	490380000
CY2016Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	505341000
CY2017Q4	us-gaap	Long Term Investments LongTermInvestments	8629000
CY2016Q4	us-gaap	Long Term Investments LongTermInvestments	8417000
CY2017Q4	us-gaap	Loss Contingency Estimate Of Possible Loss LossContingencyEstimateOfPossibleLoss	1000000
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-24771000
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-4062000
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	38430000
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-24771000
CY2016	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	-4062000
CY2015	us-gaap	Net Cash Provided By Used In Financing Activities Continuing Operations NetCashProvidedByUsedInFinancingActivitiesContinuingOperations	38114000
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-132590000
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-159324000
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-155970000
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-132590000
CY2016	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-159324000
CY2015	us-gaap	Net Cash Provided By Used In Investing Activities Continuing Operations NetCashProvidedByUsedInInvestingActivitiesContinuingOperations	-193602000
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	173577000
CY2016	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	43873000
CY2015	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	13782000
CY2016	us-gaap	Proceeds From Issuance Of Long Term Debt ProceedsFromIssuanceOfLongTermDebt	130000000
CY2017	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	69488000
CY2016	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	-37789000
CY2017	us-gaap	Net Income Loss NetIncomeLoss	72439000
CY2016	us-gaap	Net Income Loss NetIncomeLoss	62321000
CY2015	us-gaap	Net Income Loss NetIncomeLoss	59345000
CY2017Q4	us-gaap	Net Regulatory Assets NetRegulatoryAssets	-90454000
CY2016Q4	us-gaap	Net Regulatory Assets NetRegulatoryAssets	67664000
CY2017	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	2632000
CY2016	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	2905000
CY2015	us-gaap	Nonoperating Income Expense NonoperatingIncomeExpense	2177000
CY2017Q4	us-gaap	Notes Payable Related Parties Classified Current NotesPayableRelatedPartiesClassifiedCurrent	61908000
CY2016Q4	us-gaap	Notes Payable Related Parties Classified Current NotesPayableRelatedPartiesClassifiedCurrent	38519000
CY2017Q4	us-gaap	Notes Receivable Related Parties Current NotesReceivableRelatedPartiesCurrent	1752000
CY2016Q4	us-gaap	Notes Receivable Related Parties Current NotesReceivableRelatedPartiesCurrent	1671000
CY2017Q4	us-gaap	Notes Receivable Related Parties Noncurrent NotesReceivableRelatedPartiesNoncurrent	79611000
CY2016Q4	us-gaap	Notes Receivable Related Parties Noncurrent NotesReceivableRelatedPartiesNoncurrent	79843000
CY2017	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	3
CY2017	us-gaap	Operating Income Loss OperatingIncomeLoss	126134000
CY2016	us-gaap	Operating Income Loss OperatingIncomeLoss	111099000
CY2015	us-gaap	Operating Income Loss OperatingIncomeLoss	109214000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	34274000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	6013000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	2200000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	2675000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	4798000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	5618000
CY2017Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	12970000
CY2017	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	7110000
CY2016	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	7565000
CY2015	us-gaap	Operating Leases Rent Expense Net OperatingLeasesRentExpenseNet	6447000
CY2017Q4	us-gaap	Other Assets Current OtherAssetsCurrent	12491000
CY2016Q4	us-gaap	Other Assets Current OtherAssetsCurrent	8144000
CY2017Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	36006000
CY2016Q4	us-gaap	Other Assets Noncurrent OtherAssetsNoncurrent	34104000
CY2017	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	629000
CY2016	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	628000
CY2015	us-gaap	Other Comprehensive Income Loss Amortization Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Prior Service Cost Credit Before Tax OtherComprehensiveIncomeLossAmortizationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetPriorServiceCostCreditBeforeTax	821000
CY2017	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	65000
CY2016	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-11000
CY2015	us-gaap	Other Comprehensive Income Loss Available For Sale Securities Adjustment Net Of Tax OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax	-34000
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1831000
CY2016	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	98000
CY2015	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	765000
CY2015	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	765000
CY2016	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	98000
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1831000
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	1896000
CY2016	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-109000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Adjustment Net Of Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax	-799000
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-3791000
CY2016	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	-445000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Net Unamortized Gain Loss Arising During Period Before Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax	510000
CY2017	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	1266000
CY2016	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-74000
CY2015	us-gaap	Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans Tax OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax	-532000
CY2015	us-gaap	Proceeds From Repayments Of Short Term Debt ProceedsFromRepaymentsOfShortTermDebt	69818000
CY2016Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	62571000
CY2017Q4	us-gaap	Other Receivables Net Current OtherReceivablesNetCurrent	7761000
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	15000
CY2016	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	3000
CY2015	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci For Sale Of Securities Before Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax	3000
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	115000
CY2016	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-14000
CY2015	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Before Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax	-49000
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	35000
CY2016	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-6000
CY2015	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax	-18000
CY2017	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	43240000
CY2016	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	40264000
CY2015	us-gaap	Other Cost And Expense Operating OtherCostAndExpenseOperating	40021000
CY2017Q4	us-gaap	Other Deferred Credits Noncurrent OtherDeferredCreditsNoncurrent	3329000
CY2016Q4	us-gaap	Other Deferred Credits Noncurrent OtherDeferredCreditsNoncurrent	7492000
CY2017Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	11389000
CY2016Q4	us-gaap	Other Liabilities Current OtherLiabilitiesCurrent	12083000
CY2017Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	22769000
CY2016Q4	us-gaap	Other Liabilities Noncurrent OtherLiabilitiesNoncurrent	21706000
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-10000
CY2016	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-7000
CY2015	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	80000
CY2017Q4	us-gaap	Other Postretirement Defined Benefit Plan Liabilities Noncurrent OtherPostretirementDefinedBenefitPlanLiabilitiesNoncurrent	69774000
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CY2017	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	132913000
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CY2015	us-gaap	Payments To Acquire Productive Assets PaymentsToAcquireProductiveAssets	160084000
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CY2015	us-gaap	Proceeds From Divestiture Of Businesses ProceedsFromDivestitureOfBusinesses	39401000
CY2017	us-gaap	Proceeds From Issuance Of Common Stock ProceedsFromIssuanceOfCommonStock	4349000
CY2017	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	4491000
CY2016	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	4837000
CY2015	us-gaap	Proceeds From Sale Of Productive Assets ProceedsFromSaleOfProductiveAssets	3590000
CY2016	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	256000
CY2017Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	2339022000
CY2016Q4	us-gaap	Property Plant And Equipment Gross PropertyPlantAndEquipmentGross	2225444000
CY2017Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1539603000
CY2016Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	1477225000
CY2017Q4	us-gaap	Property Plant And Equipment Other PropertyPlantAndEquipmentOther	216937000
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	us-gaap	Public Utilities Interim Rate Increase Decrease Amount PublicUtilitiesInterimRateIncreaseDecreaseAmount	23289000
CY2017	us-gaap	Regulatory Asset Amortization Period RegulatoryAssetAmortizationPeriod
CY2016	us-gaap	Regulatory Asset Amortization Period RegulatoryAssetAmortizationPeriod
CY2017Q4	us-gaap	Regulatory Assets RegulatoryAssets	152127000
CY2016Q4	us-gaap	Regulatory Assets RegulatoryAssets	153391000
CY2017Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	22551000
CY2016Q4	us-gaap	Regulatory Assets Current RegulatoryAssetsCurrent	21297000
CY2017Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	129576000
CY2016Q4	us-gaap	Regulatory Assets Noncurrent RegulatoryAssetsNoncurrent	132094000
CY2017Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	242581000
CY2016Q4	us-gaap	Regulatory Liabilities RegulatoryLiabilities	85727000
CY2017	us-gaap	Regulatory Liability Amortization Period RegulatoryLiabilityAmortizationPeriod
CY2016	us-gaap	Regulatory Liability Amortization Period RegulatoryLiabilityAmortizationPeriod
CY2017Q4	us-gaap	Regulatory Liability Current RegulatoryLiabilityCurrent	9688000
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CY2016Q4	us-gaap	Regulatory Liability Noncurrent RegulatoryLiabilityNoncurrent	82433000
CY2017	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	48231000
CY2016	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	87547000
CY2015	us-gaap	Repayments Of Long Term Debt RepaymentsOfLongTermDebt	212000
CY2017Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	161286000
CY2016Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	139479000
CY2017	us-gaap	Revenues Revenues	849350000
CY2016	us-gaap	Revenues Revenues	803539000
CY2015	us-gaap	Revenues Revenues	779804000
CY2017	us-gaap	Sales Revenue Goods Net SalesRevenueGoodsNet	414844000
CY2016	us-gaap	Sales Revenue Goods Net SalesRevenueGoodsNet	376190000
CY2015	us-gaap	Sales Revenue Goods Net SalesRevenueGoodsNet	372765000
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	3642000
CY2016	us-gaap	Share Based Compensation ShareBasedCompensation	3178000
CY2015	us-gaap	Share Based Compensation ShareBasedCompensation	1716000
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
CY2016	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	75000
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
CY2016	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod	2500
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
CY2016	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice	24.93
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
CY2015Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	12750
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
CY2016Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
CY2015Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	24.93
CY2017Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
CY2017	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
CY2016	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	24.93
CY2017Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	112371000
CY2016Q4	us-gaap	Short Term Borrowings ShortTermBorrowings	42883000
CY2017Q4	us-gaap	Short Term Debt Weighted Average Interest Rate ShortTermDebtWeightedAverageInterestRate	0.027
CY2017	us-gaap	Shortterm Debt Average Outstanding Amount ShorttermDebtAverageOutstandingAmount	71696000
CY2017Q4	us-gaap	Shortterm Debt Maximum Amount Outstanding During Period ShorttermDebtMaximumAmountOutstandingDuringPeriod	112371000
CY2016Q4	us-gaap	Standard Product Warranty Accrual StandardProductWarrantyAccrual	1369000
CY2015Q4	us-gaap	Standard Product Warranty Accrual StandardProductWarrantyAccrual	2103000
CY2017Q4	us-gaap	Standard Product Warranty Accrual StandardProductWarrantyAccrual	497000
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CY2017	us-gaap	Standard Product Warranty Accrual Payments StandardProductWarrantyAccrualPayments	112000
CY2016	us-gaap	Standard Product Warranty Accrual Payments StandardProductWarrantyAccrualPayments	24000
CY2017	us-gaap	Standard Product Warranty Accrual Preexisting Increase Decrease StandardProductWarrantyAccrualPreexistingIncreaseDecrease	-760000
CY2016	us-gaap	Standard Product Warranty Accrual Preexisting Increase Decrease StandardProductWarrantyAccrualPreexistingIncreaseDecrease	-710000
CY2017	us-gaap	Standard Product Warranty Accrual Warranties Issued StandardProductWarrantyAccrualWarrantiesIssued
CY2016	us-gaap	Standard Product Warranty Accrual Warranties Issued StandardProductWarrantyAccrualWarrantiesIssued
CY2017	us-gaap	Stock Issued During Period Shares Employee Stock Ownership Plan StockIssuedDuringPeriodSharesEmployeeStockOwnershipPlan	14835
CY2017	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised
CY2016	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	10250
CY2015	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	18168000
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CY2017	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	4969000
CY2015	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	1596000
CY2016	us-gaap	Stock Repurchased And Retired During Period Value StockRepurchasedAndRetiredDuringPeriodValue	104000
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CY2015Q4	us-gaap	Stockholders Equity StockholdersEquity	605023000
CY2016Q4	us-gaap	Stockholders Equity StockholdersEquity	670104000
CY2017Q4	us-gaap	Stockholders Equity StockholdersEquity	696892000
CY2017Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	22427000
CY2016Q4	us-gaap	Unbilled Receivables Current UnbilledReceivablesCurrent	20080000
CY2015	us-gaap	Unrealized Gain Loss On Derivatives And Commodity Contracts UnrealizedGainLossOnDerivativesAndCommodityContracts	14736000
CY2016Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	891000
CY2015Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	468000
CY2014Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	222000
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	684000
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions	378000
CY2016	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsDecreasesResultingFromPriorPeriodTaxPositions
CY2017	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities
CY2016	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities	97000
CY2015	us-gaap	Unrecognized Tax Benefits Decreases Resulting From Settlements With Taxing Authorities UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	143000
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	114000
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	10000
CY2017	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	28000
CY2016	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	406000
CY2015	us-gaap	Unrecognized Tax Benefits Increases Resulting From Prior Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions	236000
CY2017Q4	us-gaap	Unrecognized Tax Benefits Interest On Income Taxes Accrued UnrecognizedTaxBenefitsInterestOnIncomeTaxesAccrued	0
CY2017	us-gaap	Use Of Estimates UseOfEstimates	<div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style="display: inline; font-family: times new roman; font-size: 10pt"><div style=" margin: 0pt; text-align: left; font-family: Times New Roman, Times, serif; font-size: 10pt;"><div style="display: inline; text-decoration: underline;">U</div><div style="display: inline; font-family: Times New Roman, Times, serif; font-size: 10pt;"><div style="display: inline; text-decoration: underline;">se of Estimates</div></div></div> <div style=" margin: 0pt; text-align: left; font-family: Times New Roman, Times, serif; font-size: 10pt;">The Company uses estimates based on the best information available in recording transactions and balances resulting from business operations. As better information becomes available (or actual amounts are known), the recorded estimates are revised. Consequently, operating results can be affected by revisions to prior accounting estimates.</div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
CY2017	us-gaap	Utilities Operating Expense Fuel Used UtilitiesOperatingExpenseFuelUsed	59690000
CY2016	us-gaap	Utilities Operating Expense Fuel Used UtilitiesOperatingExpenseFuelUsed	54792000
CY2015	us-gaap	Utilities Operating Expense Fuel Used UtilitiesOperatingExpenseFuelUsed	42744000
CY2017	us-gaap	Utilities Operating Expense Other UtilitiesOperatingExpenseOther	151319000
CY2016	us-gaap	Utilities Operating Expense Other UtilitiesOperatingExpenseOther	151225000
CY2015	us-gaap	Utilities Operating Expense Other UtilitiesOperatingExpenseOther	140768000
CY2017	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	291086
CY2016	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	184551
CY2015	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	173040
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	39748347
CY2016	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	38731010
CY2015	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	37668026
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	39457261
CY2016	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	38546459
CY2015	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	37494986

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$OTTR
Otter Tail Corp Stock $ottr

2017 Form 10-K Financial Statement

#000143774918002843 Filed on February 20, 2018

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$OTTR Otter Tail Corp Stock $ottr

2017 Form 10-K Financial Statement

#000143774918002843 Filed on February 20, 2018

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$OTTR
Otter Tail Corp Stock $ottr