Statement of Comprehensive Income [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Net Prior Service Cost (Credit) Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment, Net Unamortized Gain (Loss) Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] Accumulated Defined Benefit Plans Adjustment Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Reclassification Out Of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification Out Of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification Out Of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swaps Interest Rate Swap [Member] Commodity Contract Commodity Contract [Member] Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Interest expense Interest Costs Incurred Fuel, purchased power and cost of natural gas sold Fuel, Purchased Power and Cost of Gas Sold Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period, combined with the amount of purchased power charged against earnings for the period, and cost of gas sold to customers for the period. Operations and maintenance Operating Expense, Maintenance, Operations, and Other Costs and Expense Amount of operating expenses for the period including selling, general, and administrative expenses, costs include routine repairs and maintenance and operations. Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax benefit (expense) Income Tax Expense (Benefit) Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Discontinued Operations and Disposal Groups [Abstract] Disposal Groups, Including Discontinued Operations, Balance Sheet Accounts Disposal Groups, Including Discontinued Operations, Balance Sheet Accounts [Table Text Block] Disposal Groups, Including Discontinued Operations, Balance Sheet Accounts [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Contract or notional amounts and terms of marketing activities and derivative commodity instruments Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 Fair Value, Inputs, Level 3 [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] Business Group [Axis] Business Group [Axis] Business Group (grouping of segments) [Axis] Business Group [Domain] Business Group [Domain] [Domain] for Business Group (grouping of segments) [Axis] Utilities Group Utilities Group [Member] Utilities Group - consists of our Electric Utilities and our Gas Utilities segments Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Derivative Assets, Commodity Derivatives Derivative Asset Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Derivative Assets, Total Assets, Fair Value Disclosure Derivative Liabilities, Fair Value Disclosure Derivative Liability Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Derivative Liabilities, Total Financial and Nonfinancial Liabilities, Fair Value Disclosure Defined Benefit Plan [Abstract] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Leases [Abstract] Operating cash flows from operating leases Operating Lease, Payments Operating cash flows from finance lease Finance Lease, Interest Payment on Liability Financing cash flows from finance lease Finance Lease, Principal Payments Operating leases Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Finance leases Right-of-Use Asset Obtained in Exchange for Finance Lease Liability Organization, Consolidation and Presentation of Financial Statements [Abstract] Segment Reporting Segment Reporting, Policy [Policy Text Block] Use of Estimates and Basis of Presentation Use of Estimates, Policy [Policy Text Block] Recently Issued and Adopted Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Income Statement [Abstract] Total revenues Revenues Operating expenses: Operating Expenses [Abstract] Depreciation, depletion and amortization Depreciation, Depletion and Amortization Taxes - property and production Taxes, Miscellaneous Other operating expenses Other Cost and Expense, Operating Total operating expenses Operating Expenses Operating income Operating Income (Loss) Other income (expense): Nonoperating Income (Expense) [Abstract] Interest charges - Interest and Debt Expense [Abstract] Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) Allowance for funds used during construction - borrowed Public Utilities Allowance For Funds Used During Construction Borrowed Interest Costs Capitalized The component of the allowance for funds used during construction during the period which represents the approximate composite costs of borrowed funds and is netted against interest expense. Interest income Investment Income, Interest Allowance for funds used during construction - equity Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Other income (expense), net Other Nonoperating Income (Expense) Total other income (expense) Nonoperating Income (Expense) Income before income taxes Income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net (loss) from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income Net income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Net income available for common stock Net Income (Loss) Available to Common Stockholders, Basic Earnings per share of common stock: Earnings Per Share [Abstract] Earnings Per Share, Basic [Abstract] Earnings Per Share, Basic [Abstract] Income from continuing operations, Basic (usd per share) Income (Loss) from Continuing Operations, Per Basic Share (Loss) from discontinued operations, Basic (usd per share) Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Earnings (loss) per share, Basic (usd per share) Earnings Per Share, Basic Earnings Per Share, Diluted [Abstract] Earnings Per Share, Diluted [Abstract] Income from continuing operations, Diluted (usd per share) Income (Loss) from Continuing Operations, Per Diluted Share (Loss) from discontinued operations, Diluted (usd per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Earnings (loss) per share, Diluted (usd per share) Earnings Per Share, Diluted Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted Average Number of Shares Outstanding, Basic and Diluted [Abstract] Weighted average number of shares of common stock, basic and diluted[Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Debt Disclosure [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum Maximum [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Consolidated Indebtedness to Capitalization Ratio Debt Instrument, Consolidated Indebtedness To Capitalization Ratio Requirement For The Next Fiscal Year Debt Instrument, Consolidated Indebtedness To Capitalization Ratio Requirement For The Next Fiscal Year Recourse Leverage Ratio Recourse Leverage Ratio Recourse Leverage Ratio Debt instrument, covenant, Leverage Recourse Ratio Debt Instrument, Covenant, Recourse Leverage Ratio The maximum allowed recourse leverage ratio under debt covenants. Receivables [Abstract] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Segments [Axis] Segments [Axis] Segment [Domain] Segments [Domain] Electric Utilities Electric Utilities [Member] Electric Utilities Segment [Member] Gas Utilities Gas Utilities [Member] Gas Utilities [Member] Power Generation Power Generation [Member] Power Generation Mining Mining [Member] Mining Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Corporate Corporate, Non-Segment [Member] Accounts Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Receivable, Trade Accounts Receivable, Gross, Current Unbilled Receivables, Current Unbilled Receivables, Current Allowance for Doubtful Accounts Allowance for Doubtful Accounts Receivable, Current Accounts receivable, net Accounts Receivable, Net, Current Lessor, Lease, Description [Table] Lessor, Lease, Description [Table] Minimum Minimum [Member] Lessor, Lease, Description [Line Items] Lessor, Lease, Description [Line Items] Lessor - Lease Term Lessor, Operating Lease, Term of Contract Operating lease income Operating Lease, Lease Income Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Inter-company Revenues Intersegment Eliminations [Member] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Retail - Electric , Natural Gas and Coal Retail - Electric , Natural Gas and Coal [Member] Retail - Electric , Natural Gas and Coal Transportation Transportation [Member] Transportation [Member] Wholesale Wholesale [Member] Wholesale [Member] Market - off-system sales Market Off-System Sales [Member] Market Off-System Sales [Member] Transmission/Other Transmission/Other [Member] Transmission/Other [Member] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Other revenues Other [Member] Other [Member] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Services transferred at a point in time Transferred at Point in Time [Member] Services transferred over time Transferred over Time [Member] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Recasting of Intercompany Capital Lease Scenario, Adjustment [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Changes To Our Segment Performance Measure - Revenues Changes To Our Segment Performance Measure - Revenues Changes To Our Segment Performance Measure - Revenues Supplemental Cash Flow Information [Abstract] Supplemental Disclosure of Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Derivative [Table] Derivative [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Interest expense incurred net of amounts capitalized (including amortization of debt issuance costs, premiums and discounts) Interest Expense [Member] Cost of Sales Cost of Sales [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Derivative [Line Items] Derivative [Line Items] Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax Statement of Cash Flows [Abstract] Operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Loss from discontinued operations, net of tax Income from continuing operations Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Deferred financing cost amortization Amortization of Debt Issuance Costs and Discounts Stock compensation Share-based Compensation Deferred income taxes Deferred Income Tax Expense (Benefit) Employee benefit plans Pension and Other Postretirement Benefits Cost (Reversal of Cost) Other adjustments, net Other Noncash Income (Expense) Changes in certain operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Materials, supplies and fuel Increase (Decrease) in Inventories Accounts receivable, unbilled revenues and other operating assets Increase (Decrease) in Accounts Receivable and Other Operating Assets Accounts payable and other operating liabilities Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Regulatory assets - current Increase (Decrease) in Other Regulatory Assets Regulatory liabilities - current Increase (Decrease) in Regulatory Liabilities Other operating activities, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities of continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash provided by (used in) operating activities of discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Property, plant and equipment additions Payments to Acquire Property, Plant, and Equipment Purchase of investment Payments to Acquire Other Investments Other investing activities Payments for (Proceeds from) Other Investing Activities Net cash provided by (used in) investing activities of continuing operations Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash provided by (used in) investing activities of discontinued operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Dividends paid on common stock Payments of Dividends Common stock issued Proceeds from Issuance of Common Stock Net (payments) borrowings of short-term debt Proceeds from (Repayments of) Short-term Debt Long-term debt - repayments Repayments of Long-term Debt Distributions to noncontrolling interest Payments to Noncontrolling Interests Other financing activities Proceeds from (Payments for) Other Financing Activities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net change in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Regulatory Assets and Liabilities Disclosure [Abstract] Schedule Of Regulatory Assets And Liabilities [Table] Schedule Of Regulatory Assets And Liabilities [Table] A table of assets and liabilities that are created when regulatory agencies permit public utilities to defer recognitiion of certain revenues or costs included in rate setting. Regulatory Asset [Axis] Regulatory Asset [Axis] Regulatory Asset [Domain] Regulatory Asset [Domain] Deferred energy and fuel cost adjustments Deferred Fuel Costs [Member] Deferred gas cost adjustments Asset Recoverable Gas Costs [Member] Gas price derivatives Price Risk Derivative [Member] Deferred taxes on AFUDC Allowance For Funds Used During Construction [Member] The offsetting entry to other income when an enterprise capitalizes, as part of the cost of plant and equipment, the cost of financing construction as financed partially by equity. Employee benefit plans Pension and Other Postretirement Plans Costs [Member] Environmental Environmental [Member] Environmental costs associated with utility property [Member] Loss on reacquired debt Loss on Reacquired Debt [Member] Renewable energy standard adjustment Renewable Energy Program [Member] Deferred taxes on flow through accounting Flow Through Accounting [Member] The income tax effects of certain tax items are reflected in cost of service for the customer in which the tax benefits are realized and result in lower utiity rates. The regulatory treatment under flow-through accounting was applied for this tax benefit generated by utility costs that were previously capitalized for tax purposes in a rate case settlement and resulted in a lower rate increase. A regulatory asset was established to reflect the future increase in taxes payable recovered from sutomers as the temporarty difference reverses.[Member] Decommissioning costs Environmental Restoration Costs [Member] Gas supply contract termination Gas Supply Contract Termination [Member] Gas Supply Contract Termination [Member] Other regulatory assets Other Regulatory Assets [Member] Other regulatory assets [Member] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Deferred energy and gas costs Cost of removal Removal Costs [Member] Excess deferred income taxes Deferred Income Tax Charges a [Member] Rate Action of a regulator resulting in capitalization or accrual of income taxes TCJA revenue reduction Revenue Subject to Refund [Member] Other regulatory liabilities Other Regulatory Liabilities [Member] Other regulatory liabilities [Member] Schedule Of Regulatory Assets And Liabilities [Line Items] Schedule Of Regulatory Assets And Liabilities [Line Items] Schedule of regulatory asset and liabilities line items Regulatory assets Net Regulatory Assets [Abstract] Regulatory assets Regulatory Assets Less current regulatory assets Regulatory Assets, Current Regulatory assets, non-current Regulatory Assets, Noncurrent Regulatory liabilities Regulatory Assets and Liabilities, Other Disclosures [Abstract] Regulatory liabilities Regulatory Liabilities Less current regulatory liabilities Regulatory Liability, Current Regulatory liabilities, non-current Regulatory Liability, Noncurrent Regulatory Accounting Schedule of Regulatory Assets and Liabilities [Text Block] Statement of Stockholders' Equity [Abstract] Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] AOCI Attributable to Parent AOCI Attributable to Parent [Member] Noncontrolling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Treasury Stock, Shares Treasury Stock, Shares Total Equity, beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Net income available for common stock Other comprehensive income Other Comprehensive Income (Loss), Net of Tax Dividends on common stock Dividends, Common Stock, Cash Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Share-based compensation Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Shares, New Issues Stock Issued During Period, Shares, New Issues Stock Issued During Period, Value, New Issues Stock Issued During Period, Value, New Issues Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Cumulative Effect of New Accounting Principle in Period of Adoption Cumulative Effect of New Accounting Principle in Period of Adoption Stock Issued During Period, Shares, Dividend Reinvestment Plan Stock Issued During Period, Shares, Dividend Reinvestment Plan Dividend reinvestment and stock purchase plan Stock Issued During Period, Value, Dividend Reinvestment Plan Other stock transactions Stockholders' Equity, Other Distribution to noncontrolling interest Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Total Equity, ending balance Notes Payable, Current Maturities and Debt Debt Disclosure [Text Block] Earnings Per Share Earnings Per Share [Text Block] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Deferred Derivative Gain (Loss) Deferred Derivative Gain (Loss) [Member] Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net Regulatory assets Non-cash Investing and Financing Activities from Continuing Operations [Abstract] Noncash Investing and Financing Items [Abstract] Property, plant and equipment acquired with accrued liabilities Capital Expenditures Incurred but Not yet Paid Supplemental Cash Flow Elements [Abstract] Supplemental Cash Flow Elements [Abstract] Interest (net of amounts capitalized) Interest Paid, Excluding Capitalized Interest, Operating Activities Income taxes Income Taxes Paid, Net Operating Leases Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] 2019 Lessor, Operating Lease, Payments to be Received, Remainder of Fiscal Year 2020 Lessor, Operating Lease, Payments to be Received, Two Years 2021 Lessor, Operating Lease, Payments to be Received, Three Years 2022 Lessor, Operating Lease, Payments to be Received, Four Years 2023 Lessor, Operating Lease, Payments to be Received, Five Years Thereafter Lessor, Operating Lease, Payments to be Received, Thereafter Total lease receivables Lessor, Operating Lease, Payments to be Received Equity Stockholders' Equity Note Disclosure [Text Block] Schedule of Net Benefit Costs Schedule of Net Benefit Costs [Table Text Block] Schedule of Defined Benefit Plans Contributions Schedule of Defined Benefit Plans Contributions [Table Text Block] Schedule of Defined Benefit Plans Contributions for the current year and specific future years.[Text Block] Income Tax Disclosure [Abstract] Income tax benefit for deferred tax amortization related to tax reform Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Payables and Accruals [Abstract] Schedule of Accrued Liabilities Schedule of Accrued Liabilities [Table Text Block] Segment Reporting Information, Additional Information [Abstract] Business Segment Information Segment Reporting Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Restricted Net Assets for Subsidiaries Restricted Net Assets for Subsidiaries Amount of Restricted Net Assets (Equity) for Subsidiaries as of the end of the reporting period. Supplemental Disclosure of Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Inventory, Net [Abstract] Materials, Supplies and Fuel Inventory Disclosure [Text Block] Segment Reporting Schedule of Segment Reporting Information, by Segment [Table Text Block] Reconciliation of Assets from Segment to Consolidated Reconciliation of Assets from Segment to Consolidated [Table Text Block] Management's Statement Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Reclassification adjustment of benefit plan - prior service cost, (tax) benefit Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, Tax Reclassification adjustment of benefit plan liabilities, (tax) benefit Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Net unrealized gains/losses, (tax) benefit Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Reclassification of net realized gains/losses, (tax) benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Schedule of Earnings Per Share Reconciliation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Operating Leases Operating Lease Liabilities, Payments Due [Abstract] 2019 Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2020 Lessee, Operating Lease, Liability, Payments, Due Year Two 2021 Lessee, Operating Lease, Liability, Payments, Due Year Three 2022 Lessee, Operating Lease, Liability, Payments, Due Year Four 2023 Lessee, Operating Lease, Liability, Payments, Due Year Five Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total lease payments Lessee, Operating Lease, Liability, Payments, Due Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Present Value of Lease Liabilities - Operating leases Operating Lease, Liability Finance Leases Finance Lease Liabilities, Payments, Due [Abstract] 2019 Finance Lease, Liability, Payments, Remainder of Fiscal Year 2020 Finance Lease, Liability, Payments, Due Year Two 2021 Finance Lease, Liability, Payments, Due Year Three 2022 Finance Lease, Liability, Payments, Due Year Four 2023 Finance Lease, Liability, Payments, Due Year Five Thereafter Finance Lease, Liability, Payments, Due after Year Five Total lease payments Finance Lease, Liability, Payments, Due Less imputed interest Finance Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities - Finance Leases Finance Lease, Liability Operating and Finance Lease Total Operating and Finance Lease Total [Abstract] Operating and Finance Lease Total [Abstract] 2019 Lease Liability Payments Remainder of Fiscal Year Lease Liability Payments Remainder of Fiscal Year 2020 Lease Liability Payments Due Year Two Lease Liability Payments Due Year Two 2021 Lease Liability Payments Due Year Three Lease Liability Payments Due Year Three 2022 Lease Liability Payments Due Year Four Lease Liability Payments Due Year Four 2023 Lease Liability Payments Due Year Five Lease Liability Payments Due Year Five Thereafter Lease Liability Payments After Year Five Lease Liability Payments After Year Five Total lease payments Lease Liability Payments Due Lease Liability Payments Due Less imputed interest Lease Liability Undiscounted Excess Amount Lease Liability Undiscounted Excess Amount Present value of lease liabilities Lease Liability Lease Liability Prior Year End Operating Lease Future Minimum Payments Prior Year End Operating Lease Future Minimum Payments [Abstract] Prior Year End Operating Lease Future Minimum Payments [Abstract] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total lease payments Operating Leases, Future Minimum Payments Due Lessee, Operating Leases Lessee, Operating Leases [Text Block] Lessee, Finance Leases Lessee, Finance Leases [Text Block] Lessor, Operating Leases Lessor, Operating Leases [Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash and Investments, Current Accounts receivable, net Materials, supplies and fuel Inventory, Net Derivative assets, current Derivative Asset, Current Income tax receivable, net Income Taxes Receivable, Current Regulatory assets, current Other current assets Other Assets, Current Current assets held for sale Disposal Group, Including Discontinued Operation, Assets, Current Total current assets Assets, Current Investments Long-term Investments Property, plant and equipment Property, Plant and Equipment, Gross Less: accumulated depreciation and depletion Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property, plant and equipment, net Property, Plant and Equipment, Net Other assets: Other Assets, Noncurrent [Abstract] Goodwill Goodwill Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Other assets, non-current Other Assets, Noncurrent Total other assets, non-current Assets, Noncurrent, Other than Noncurrent Investments and Property, Plant and Equipment TOTAL ASSETS Assets LIABILITIES AND TOTAL EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Derivative liabilities, current Derivative Liability, Current Regulatory liabilities, current Notes payable Short-term Debt Current maturities of long-term debt Long-term Debt, Current Maturities Current liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities, Current Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Deferred credits and other liabilities: Liabilities, Noncurrent [Abstract] Deferred income tax liabilities, net Deferred Tax Liabilities, Net, Noncurrent Benefit plan liabilities Liability, Defined Benefit Plan, Noncurrent Other deferred credits and other liabilities Other Liabilities, Noncurrent Total deferred credits and other liabilities Liabilities, Noncurrent Commitments and contingencies (See Notes 8, 10, 15, 16) Commitments and Contingencies Equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock $1 par value; 100,000,000 shares authorized; issued 60,378,020; 60,048,567; and 53,648,817 shares, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock, at cost – 23,756; 44,253; and 53,959 shares, respectively Treasury Stock, Value Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Stockholders' Equity Attributable to Parent Noncontrolling interest Noncontrolling Interest in Variable Interest Entity Total equity TOTAL LIABILITIES AND TOTAL EQUITY Liabilities and Equity Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of Assets from Segment to Consolidated [Table] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued Operations, Held-for-sale Discontinued Operations, Held-for-sale [Member] Segment Reporting, Asset Reconciling Item [Line Items] Segment Reporting, Asset Reconciling Item [Line Items] Assets Changes To Our Segment Performance Measure - Assets Changes To Our Segment Performance Measure - Assets Changes To Our Segment Performance Measure - Assets Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] Income Tax Expense (Benefit) Income tax expense (benefit) associated with changes in the prior estimated impact of tax reform on deferred income taxes Increase in income tax benefit from forecasted federal production tax credits and state investment tax credits Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Other Restructuring Other Restructuring [Member] Deferred Tax Assets, Goodwill and Intangible Assets Deferred Tax Assets, Goodwill and Intangible Assets Materials, Supplies and Fuel Schedule of Inventory, Current [Table Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2016-02 [Member] Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating lease - right of use assets Operating Lease, Right-of-Use Asset Operating lease liabilities Accrued Rent Receivable Deferred Rent Receivables, Net Schedule of Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities [Table Text Block] The entire disclosure for detailed information about regulatory assets and liabilities, including current and noncurrent assets created when regulatory agencies permit the deferral of costs to the balance sheet that would otherwise be required to appear on the company's income statement and would be charged against current expenses or revenues, as well as current and noncurrent liabilities created when regulatory agencies permit. [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Derivative assets — current Derivative Assets, Current [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Other assets, non-current Derivative Assets, Noncurrent [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Derivative liabilities — current Derivative Liabilities, Current [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Other deferred credits and other liabilities Derivative Liabilities, Noncurrent [Member] Line item in the statement of financial position in a classified presentation in which the fair value amounts of the derivative instruments are included. Derivatives, Carrying Amount and Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative Asset, Fair Value, Gross Asset Derivative Asset, Fair Value, Gross Asset Derivative Liability, Fair Value, Gross Liability Derivative Liability, Fair Value, Gross Liability Derivative Asset, Fair Value, Net Derivative Asset, Fair Value, Amount Not Offset Against Collateral Accrued employee compensation, benefits and withholdings Employee-related Liabilities, Current Accrued property taxes Accrual for Taxes Other than Income Taxes, Current Customer deposits and prepayments Customer Deposits and Prepayments Accrued Liabilities - Customer Deposits and Prepayments Accrued interest and contract adjustment payments Interest Payable, Current CIAC current portion Contributions in Aid of Construction Other (none of which is individually significant) Other Accrued Liabilities, Current Total accrued liabilities Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] At The Market Equity Offering Program Authorized Aggregate Value At The Market Equity Offering Program Authorized Aggregate Value At The Market Equity Offering Program authorized an aggregate value that the Company may, through its sales agents, offer and sell from time to time shares of its common stock. At The Market Equity Offering Program Shares Issued At The Market Equity Offering Program Shares Issued At The Market Equity Offering Program Shares Issued At The Market Equity Program Proceeds from Sale of Stock At The Market Equity Program Proceeds from Sale of Stock At The Market Equity Program Proceeds from Sale of Stock Payments of Stock Issuance Costs Payments of Stock Issuance Costs Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Interest Rate Swaps Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax [Roll Forward] Accumulated Other Comprehensive Income [Roll Forward] Accumulated Other Comprehensive Income [Roll Forward] Accumulated Other Comprehensive Income (Loss), Net of Tax, Period Start Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Reclassification from AOCI, Current Period, Tax Reclassification from AOCI, Current Period, Tax Accumulated Other Comprehensive Income (Loss), Net of Tax, Period End Weighted average shares - basic (in shares) Dilutive effect of: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Equity Units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Equity Unit Purchase Agreements Equity compensation (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average shares - diluted (in shares) Fair Value of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Operating lease assets Finance lease assets Finance Lease, Right-of-Use Asset Total lease assets Operating and Finance Lease Assets Operating and Finance Lease Assets Operating lease liability, current Operating Lease, Liability, Current Finance lease liability, current Finance Lease, Liability, Current Operating lease liability, non-current Operating Lease, Liability, Noncurrent Finance lease liability, non-current Finance Lease, Liability, Noncurrent Total lease liabilities Operating and Finance Lease Liabilities Operating and Finance Lease Liabilities Fair Value Measurements Derivatives and Fair Value [Text Block] Document and Entity Information [Abstract] Abstract model section heading for document and entity information Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract] Other current assets Disposal Group, Including Discontinued Operation, Other Assets, Current Deferred income tax assets, noncurrent, net Disposal Group, Including Discontinued Operation, Deferred Tax Assets, Noncurrent Property, plant and equipment, net Disposal Group, Including Discontinued Operation, Property, Plant and Equipment Other current liabilities Disposal Group, Including Discontinued Operation, Other Liabilities Other noncurrent liabilities Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent Net (liabilities) Disposal Group, Including Discontinued Operation, Liabilities Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Commercial Paper Commercial Paper [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Base Rate Base Rate [Member] Eurodollar Eurodollar [Member] Letter of Credit Letter of Credit [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Letters of Credit Letters of Credit Outstanding, Amount Current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Number of one-year extension options Number Of One-Year Extension Options Number Of One-Year Extension Options Debt instrument, term Debt Instrument, Term Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Interest rate Line of Credit Facility, Interest Rate at Period End Commitment fee Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Commercial paper, maximum borrowing capacity Commercial Paper, Maximum Borrowing Capacity Commercial Paper, Maximum Borrowing Capacity Short-term interest rate Short-term Debt, Weighted Average Interest Rate, at Point in Time Risk Management Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Reclassification Out of Accumulated Other Comprehensive Income (Loss) Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Application Filed Application Filed [Member] Application Filed [Member] Rate Review Filed with the Regulatory Agency Rate Review Filed with the Regulatory Agency [Member] Rate Review Filed with the Regulatory Agency [Member] Regulatory Agency [Axis] Regulatory Agency [Axis] Regulatory Agency [Domain] Regulatory Agency [Domain] Nebraska Public Service Commission (NPSC) Nebraska Public Service Commission (NPSC) [Member] Nebraska Public Service Commission (NPSC) [Member] Wyoming Public Service Commission (WPSC) Wyoming Public Service Commission (WPSC) [Member] Wyoming Public Service Commission (WPSC) [Member] Colorado Public Utilities Commission (CPUC) Colorado Public Utilities Commission (CPUC) [Member] Colorado Public Utilities Commission (CPUC) [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Black Hills Energy, Nebraska Gas Black Hills Energy, Nebraska Gas [Member] Black Hills Energy, Nebraska Gas [Member] Black Hills Energy, Wyoming Gas Black Hills Energy, Wyoming Gas [Member] Black Hills Energy, Wyoming Gas [Member] Black Hills Energy, Colorado Gas Black Hills Energy, Colorado Gas [Member] Black Hills Energy, Colorado Gas [Member] Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Public Utilities, Number of Companies Being Merged Public Utilities, Number of Companies Being Merged Public Utilities, Number of Companies Being Merged Public Utilities, Requested Rate Increase, Amount Public Utilities, Requested Rate Increase (Decrease), Amount Materials and supplies Inventory, Raw Materials and Supplies, Gross Fuel - Electric Utilities Energy Related Inventory, Other Fossil Fuel Natural gas in storage held for distribution Energy Related Inventory, Natural Gas in Storage Total materials, supplies and fuel Revenue Revenue from Contract with Customer [Text Block] Operating leases Operating Lease, Weighted Average Remaining Lease Term Finance leases Finance Lease, Weighted Average Remaining Lease Term Operating leases Operating Lease, Weighted Average Discount Rate, Percent Finance leases Finance Lease, Weighted Average Discount Rate, Percent Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Defined Benefit Pension Plans Pension Plan [Member] Defined Benefit Postretirement Healthcare Plans Other Postretirement Benefits Plan [Member] Supplemental Non-qualified Defined Benefit and Defined Contribution Plans Supplemental Employee Retirement Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Prior service cost (benefit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Net loss (gain) Defined Benefit Plan, Amortization of Gain (Loss) Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Payment for Pension and Other Postretirement Benefits [Abstract] Payment for Pension and Other Postretirement Benefits [Abstract] Contributions by Employer Defined Benefit Plan, Plan Assets, Contributions by Employer Estimated Future Employer Contributions in Current Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year Estimated Future Employer Contributions in Next Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Accounts Receivable and Allowance for Doubtful Accounts Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Common Stock, Par Value (usd per share) Common Stock, Par or Stated Value Per Share Common Stock, Shares Issued Common Stock, Shares, Issued Common Stock, Shares Authorized Common Stock, Shares Authorized Schedule of Fair Value Hierarchy, Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Derivative Instruments Balance Sheet Location Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Dividends per share of common stock (usd per share) Common Stock, Dividends, Per Share, Cash Paid Energy [Axis] Energy [Axis] Energy [Domain] Energy [Domain] Natural Gas, Distribution Natural Gas, Distribution [Member] Natural Gas for distribution [Member] Natural gas futures purchased Future [Member] Natural gas options purchased, net Commodity Option [Member] Natural gas basis swaps purchased Basis Swap [Member] Natural gas over-the-counter swaps, net Fixed for Float Swaps Purchased [Member] Fixed for Float Swaps Purchased [Member] Natural gas physical contracts, net Natural Gas Physical Purchases [Member] Natural Gas Physical Purchases [Member] Derivative, Nonmonetary Notional Amount Derivative, Nonmonetary Notional Amount Derivative, Remaining Maturity Derivative, Remaining Maturity Derivative, Nonmonetary Notional Amount, Energy Measure Derivative, Nonmonetary Notional Amount, Energy Measure Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Credit Risk Derivative Liabilities, at Fair Value Collateral Already Posted, Aggregate Fair Value Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] External Operating Revenue External Customers [Member] External Customers Inter-company Operating Revenue Intercompany Customers [Member] Intercompany Customers [Member] Other Revenues Consolidation, Eliminations Consolidation, Eliminations [Member] Segment Reconciling Items [Member] Segment Reconciling Items [Member] Segment Reporting Information Segment Reporting Information [Line Items] Revenues Operating income Interest expense, net Interest Income (Expense), Net Other income (expense), net Other Nonoperating Expense Changes To Our Segment Performance Measure - Operating Income Changes To Our Segment Performance Measure - Operating Income Changes To Our Segment Performance Measure - Operating Income Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Lessee - Lease Term Lessee - Lease Term Lessee - Lease Term Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Schedule of Stockholders Equity Schedule of Stockholders Equity [Table Text Block] Lessee Disclosure [Abstract] Lease, Cost Lease, Cost [Table Text Block] Lessee - Supplemental Balance Sheet Information Lessee Supplemental Balance Sheet Information Related to Leases [Table Text Block] Lessee Supplemental Balance Sheet Information Related to Leases [Table Text Block] Lessee - Supplemental Cash Flow Information Lessee Supplemental Cash Flow Information Related to Leases [Table Text Block] Lessee Supplemental Cash Flow Information Related to Leases [Table Text Block] Lessee - Supplemental Weighted Average Schedule Lessee Supplemental Weighted Average Schedule Related to Leases [Table Text Block] Lessee Supplemental Weighted Average Schedule Related to Leases [Table Text Block] Lessee, Operating Lease, Liability, Maturity Lessee, Operating Lease, Liability, Maturity [Table Text Block] Lessee - Finance Lease, Liability, Maturity Finance Lease, Liability, Maturity [Table Text Block] Lessor Disclosure [Abstract] Operating Lease, Lease Income Operating Lease, Lease Income [Table Text Block] Lessor - Operating and Finance Lease, Liability, Maturity Schedule Of Maturities of Operating And Finance Lease Receivable [Table Text Block] Schedule Of Maturities of Operating And Finance Lease Receivable [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Operating lease cost Operating Lease, Cost Amortization of right-of-use asset Finance Lease, Right-of-Use Asset, Amortization Interest on lease liabilities Finance Lease, Interest Expense Total lease cost Lease, Cost Other comprehensive income (loss), net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Reclassification adjustments of benefit plan liability - prior service cost Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax Reclassification adjustments of benefit plan liability - net gain (loss) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax Reclassification of net realized (gains) losses Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net unrealized gains (losses) Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Other comprehensive income, net of tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: comprehensive income attributable to noncontrolling interest Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Comprehensive income available for common stock Comprehensive Income (Loss), Net of Tax, Attributable to Parent Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Carrying Amount Reported Value Measurement [Member] Fair Value Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and cash equivalents, Fair Value Cash and Cash Equivalents, Fair Value Disclosure Restricted Cash Fair Value Disclosure Restricted Cash Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This element represents the fair value of assets categorized as restricted cash Notes payable, Fair Value Short-term Debt, Fair Value Long-term debt, including current maturities Long-term Debt Long-term debt, including current maturities, Fair Value Long-term Debt, Fair Value Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Equity compensation Stock Compensation Plan [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Anti-dilutive shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Schedule of Short-term Debt Schedule of Short-term Debt [Table Text Block] Schedule of Credit Facility Covenants Credit Facility and Short Term Debt Covenants [Table Text Block] Schedule of significant debt covenants related to Credit Facility and other short-term debt [Table Text Block] Accrued Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block]