Statement of Comprehensive Income [Abstract] Foreign currency translation, tax impact Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax Cash flow hedges, tax impact Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Reclassifications to net loss, tax impact (less than) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Equity method investee, tax impact Other Comprehensive Income (Loss), Share Equity Method Investee, Tax Proportionate share of equity investee's other comprehensive (loss) income activity, net of tax benefit (provision). Comprehensive loss attributable to noncontrolling interests, tax impact (less than) Other Comprehensive Income (Loss), Tax, Portion Attributable to Noncontrolling Interest Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Operating wind farms Operating Wind Farms [Member] Operating Wind Farms [Member] Transmission line Transmission Line [Member] Transmission Line [Member] Furniture, fixtures and equipment Furniture Fixtures And Equipment [Member] Furniture Fixtures And Equipment [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, plant and equipment, gross Property, Plant and Equipment, Gross Less: accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant and equipment, net Property, Plant and Equipment, Net Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] MSM LP Holdings LP MSM LP Holdings LP [Member] MSM LP Holdings LP [Member] Asset Acquisition [Axis] Asset Acquisition [Axis] Asset Acquisition [Axis] Asset Acquisition [Domain] Asset Acquisition [Domain] [Domain] for Asset Acquisition [Axis] Mont Sainte-Marguerite Mont Sainte-Marguerite [Member] Mont Sainte-Marguerite [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Tsugaru Holdings Tsugaru Holdings [Member] Tsugaru Holdings [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] MSM Pattern MSM GP Holdings, Inc. Pattern MSM GP Holdings, Inc. [Member] Pattern MSM GP Holdings, Inc. [Member] Pattern Development MSM Management ULC Pattern Development MSM Management ULC [Member] Pattern Development MSM Management ULC [Member] Tsugaru Tsugaru [Member] Tsugaru [Member] Ohorayama Ohorayama [Member] Ohorayama [Member] Kanagi Kanagi [Member] Kanagi [Member] Otsuki Otsuki [Member] Otsuki [Member] Futtsu Futtsu [Member] Futtsu [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] Aomori Prefecture, Japan Aomori Prefecture, Japan [Member] Aomori Prefecture, Japan [Member] Kochi Prefecture, Japan Kochi Prefecture, Japan [Member] Kochi Prefecture, Japan [Member] Shimane Prefecture, Japan Shimane Prefecture, Japan [Member] Shimane Prefecture, Japan [Member] Chiba Prefecture, Japan Chiba Prefecture, Japan [Member] Chiba Prefecture, Japan [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Percentage of shares acquired Asset Acquisition Percentage Of Shares Acquired Asset Acquisition Percentage Of Shares Acquired Generating capacity Generating Capacity Power generation capacity. Consideration transferred Asset Acquisition, Consideration Transferred Asset Acquisition, Consideration Transferred Consideration Business Combination, Consideration Transferred Contingent consideration Business Combination, Contingent Consideration, Liability, Current Transaction costs Business Combination, Acquisition Related Costs Property, Plant and Equipment Property, Plant and Equipment Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Pacific US Inc. Pacific US Inc. [Member] Pacific US Inc. [Member] Merger Agreement Merger Agreement [Member] Merger Agreement [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Earnout Acquisition Agreement [Member] Earnout Acquisition Agreement [Member] Earnout Acquisition Agreement [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series A Series A Preferred Stock [Member] Common Class A Common Class A [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Pattern Development 2.0 Pattern Development 2.0 [Member] Pattern Development 2.0 [Member] Pattern Energy Group LP Pattern Energy Group LP [Member] Pattern Energy Group LP [Member] Grady, New Mexico Grady, New Mexico [Member] Grady, New Mexico [Member] Curry Country, New Mexico Curry Country, New Mexico [Member] Curry Country, New Mexico [Member] Grady and Curry Country, New Mexico Grady and Curry Country, New Mexico [Member] Grady and Curry Country, New Mexico [Member] Henvey Inlet, Ontario, Canada Henvey Inlet, Ontario, Canada [Member] Henvey Inlet, Ontario, Canada [Member] First Nation Reserve No. 2 Lands, Ontario, Canada First Nation Reserve No. 2 Lands, Ontario, Canada [Member] First Nation Reserve No. 2 Lands, Ontario, Canada [Member] Henvey Inlet First Nation Reserve No. 2 Lands, Ontario, Canada Henvey Inlet First Nation Reserve No. 2 Lands, Ontario, Canada [Member] Henvey Inlet First Nation Reserve No. 2 Lands, Ontario, Canada [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Price per share (in dollars per share) Business Acquisition, Share Price Dividends payable per share (in dollars per share) Dividends Payable, Amount Per Share Aggregate dividend Dividends Payable Dividends annualized (in dollars per share) Dividends Payable Amount Per Share Annualized Dividends payable amount per share annualized. Percent of earnout rights Related Party Transaction, Earnout Rights, Percentage Related Party Transaction, Earnout Rights, Percentage Profits interest in such projects Related Party Transaction, Profits Interest, Percentage Related Party Transaction, Profits Interest, Percentage Purchases from related party Related Party Transaction, Purchases from Related Party Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Preferred stock, value, issued Preferred Stock, Value, Issued Preferred stock, discount Preferred Stock, Discount On Shares, Percentage Preferred Stock, Discount On Shares, Percentage Preferred stock, dividend rate Preferred Stock, Dividend Rate, Percentage Preferred stock, liquidation preference per share Preferred Stock, Liquidation Preference Per Share Increase in annual dividend rate Increase In Annual Dividend Rate Increase In Annual Dividend Rate Maximum number of escalations period Maximum Number Of Escalations Maximum Number Of Escalations Preferred stock, dividend rate after maximum number of escalations Preferred Stock, Dividend Rate, After Maximum Number Of Escalations, Percentage Preferred Stock, Dividend Rate, After Maximum Number Of Escalations, Percentage Stock receivable Stock Receivable , Including Return Of Capital Stock Receivable , Including Return Of Capital Net proceeds received Proceeds from (Repayments of) Debt Statement of Stockholders' Equity [Abstract] Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Earnings Per Share [Abstract] Earnings (Loss) Per Share Earnings Per Share [Text Block] Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] PEGH 2 Investment PEGH 2 Investment [Member] PEGH 2 Investment [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Not Primary Beneficiary Variable Interest Entity, Not Primary Beneficiary [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Carrying value of unconsolidated investment Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net Leases [Abstract] Lease, Cost [Abstract] Lease, Cost [Abstract] Operating lease cost Operating Lease, Cost Sublease income Sublease Income Total lease cost Lease, Cost Lease, Supplemental Cash Flow And Other Information [Abstract] Lease, Supplemental Cash Flow And Other Information [Abstract] Lease, Supplemental Cash Flow And Other Information [Abstract] Operating cash flows from operating leases Operating Lease, Payments Right of use assets obtained in exchange for new operating lease obligations Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Weighted average remaining lease term (years) Operating Lease, Weighted Average Remaining Lease Term Weighted average discount rate Operating Lease, Weighted Average Discount Rate, Percent Business Acquisition, Pro Forma Information [Abstract] Business Acquisition, Pro Forma Information [Abstract] Pro forma total revenue Business Acquisition, Pro Forma Revenue Pro forma total expenses Business Acquisition, Pro Forma Expense Business Acquisition, Pro Forma Expense Pro forma net loss Business Acquisition, Pro Forma Net Income (Loss) Less: pro forma net loss attributable to noncontrolling interest Business Acquisition, Pro Forma Net Income (Loss), Portion Attributable to Noncontrolling Interest Business Acquisition, Pro Forma Net Income (Loss), Portion Attributable to Noncontrolling Interest Pro forma net income (loss) attributable to Pattern Energy Business Acquisition, Pro Forma Net Income (Loss), Portion Attributable to Parent Business Acquisition, Pro Forma Net Income (Loss), Portion Attributable to Parent Segment Reporting [Abstract] Number of reportable segments Number of Reportable Segments Revenue from Contract with Customer [Abstract] Revenue Revenue from Contract with Customer [Text Block] Equity [Abstract] Noncontrolling Interest [Table] Noncontrolling Interest [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Capital Capital Units [Member] Accumulated Loss Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Noncontrolling Interest [Member] Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward] Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward] Beginning balance Stockholders' Equity Attributable to Noncontrolling Interest Acquisitions Noncontrolling Interest, Increase from Business Combination Sale of subsidiaries Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Contributions from noncontrolling interests Noncontrolling Interest, Increase from Contributions Noncontrolling Interest, Increase from Contributions Distributions to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Net loss Net Income (Loss) Attributable to Noncontrolling Interest Other comprehensive loss, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest Ending balance Tax reform, change in tax rate Tax Cuts and Jobs Act, Incomplete Accounting, Change in Tax Rate, Provisional Income Tax Expense (Benefit) Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Remaining lease term Lessee, Operating Lease, Remaining Lease Term Lessee, Operating Lease, Remaining Lease Term Future Sublease Proceeds Under Sublease Arrangement Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Remainder of 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 2024 Lessor, Operating Lease, Payments to be Received, Six Years Lessor, Operating Lease, Payments to be Received, Six Years 2025 Lessor, Operating Lease, Payments to be Received, Seven Years Lessor, Operating Lease, Payments to be Received, Seven Years 2026 Lessor, Operating Lease, Payments to be Received, Eight Years Lessor, Operating Lease, Payments to be Received, Eight Years Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Subsidiary or Equity Method Investee, Sale of Stock by Subsidiary or Equity Investee [Table] Broadview Broadview [Member] Broadview [Member] Subsidiary, Sale of Stock [Line Items] Subsidiary, Sale of Stock [Line Items] Class A common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Aggregate sales price Equity Distribution Agreement Maximum Aggregate Sales Price The maximum amount of aggregate sales under the Equity Distribution Agreement Shares sold (in shares) Shares Sold Under the Equity Distribution Agreement Shares Sold Under the Equity Distribution Agreement Aggregate offering price Equity Distribution Agreement Remaining Aggregate Sales Available The remaining amount of aggregate sales available under the Equity Distribution Agreement as of the balance sheet date Pay-go contribution Noncontrolling Interest, Increase From Noncontrolling Interest Receivable Noncontrolling Interest, Increase From Noncontrolling Interest Receivable Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated Derivative Instruments Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument Not Designated as Hedging Instrument [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest rate swaps Interest Rate Swap [Member] Energy derivative Energy Related Derivative [Member] Foreign currency forward contracts Foreign Exchange Forward [Member] Congestion revenue rights Congestion Revenue Rights [Member] Congestion Revenue Rights [Member] Derivative [Line Items] Derivative [Line Items] Derivative assets, current Derivative Asset, Current Derivative assets, noncurrent Derivative Asset, Noncurrent Derivative liabilities, current Derivative Liability, Current Derivative liabilities, noncurrent Derivative Liability, Noncurrent Derivative asset (less than $1 million for congestion revenue rights in September 30, 2019) Derivative Asset Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash Restricted Cash, Current Trade receivables Accounts Receivable, after Allowance for Credit Loss, Current Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total current assets Assets, Current Restricted cash Restricted Cash, Noncurrent Construction in progress Construction in Progress, Gross Property, plant and equipment, net Unconsolidated investments Equity Method Investments Deferred financing costs, net Debt Issuance Costs, Noncurrent, Net Intangible assets, net Finite-Lived Intangible Assets, Net Other assets Other Assets, Noncurrent Total assets Assets Liabilities Liabilities [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable and other accrued liabilities Accounts Payable and Other Accrued Liabilities, Current Accrued construction costs Construction Payable, Current Current portion of long-term debt, net Long-term Debt, Current Maturities Other current liabilities Other Liabilities, Current Total current liabilities Liabilities, Current Long-term debt, net Long-term Debt, Excluding Current Maturities Intangible liability, net Finite Lived Intangible Liability Net Amount recognized as an intangible liability when the contract price is lower than the estimated fair value. Asset retirement obligations Asset Retirement Obligations, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Deferred revenue Contract with Customer, Liability, Noncurrent Total liabilities Liabilities Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Accounting Policies [Abstract] 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 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 Operating Lease, Liability Schedule of Derivative Instruments Classified as Assets (Liabilities) Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Schedule of Notional Amounts of Outstanding Derivative Positions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Table Text Block] Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location Derivatives Not Designated as Hedging Instruments [Table Text Block] Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Statement of Financial Position [Abstract] Assets Current assets: Cash and cash equivalents (Note 7) Restricted cash (Note 7) Counterparty collateral Cash Collateral from Derivative Counterparty The carrying amount of cash collateral received from hedge counterparties in support of energy risk management activities for which there is an offsetting liability within current liabilities. The Company does not have the right to pledge, invest, or use the cash collateral for general corporate purposes. Trade receivables (Note 7) Prepaid expenses (Note 7) Deferred financing costs, current, net of accumulated amortization of $4 and $3 as of September 30, 2019 and December 31, 2018, respectively Debt Issuance Costs, Current, Net Sales tax receivable Income Taxes Receivable Other current assets (Note 7) Restricted cash (Note 7) Major construction advances Turbine Advances Amounts advanced to turbine suppliers for the manufacture of wind turbines in accordance with turbine supply agreements for the Company's wind power projects and for which the Company has not taken title. Turbine advances are reclassified to construction in progress when the Company takes legal title to the related turbines and are reclassified to property, plant and equipment when the project achieves commercial operation. Depreciation does not commence until projects enter commercial operation and turbine assets are placed in service. Property, plant and equipment, net (Note 7) Unconsolidated investments (Note 7) Derivative assets Deferred financing costs Net deferred tax assets Deferred Income Tax Assets, Net Intangible assets, net (Note 7) Goodwill Goodwill Other assets (Note 7) Liabilities and equity Liabilities and Equity [Abstract] Accounts payable and other accrued liabilities (Note 7) Accrued construction costs (Note 7) Counterparty collateral liability Derivative, Collateral, Obligation to Return Cash Accrued interest (Note 7) Interest Payable, Current Dividends payable Dividends Payable, Current Revolving credit facility, current Line of Credit, Current Asset retirement obligation, current Asset Retirement Obligation, Current Contingent liabilities, current Other current liabilities (Note 7) Revolving credit facility Long-term Line of Credit, Noncurrent Derivative liabilities Net deferred tax liabilities Deferred Income Tax Liabilities, Net Intangible liabilities, net (Note 7) Contingent liabilities (Note 7) Business Combination, Contingent Consideration, Liability, Noncurrent Asset retirement obligations (Note 7) Other long-term liabilities (Note 7) Contract liability Commitments and contingencies (Note 16) Commitments and Contingencies Equity: Stockholders' Equity Attributable to Parent [Abstract] Class A common stock, $0.01 par value per share: 500,000,000 shares authorized; 98,240,118 and 98,051,629 shares outstanding as of September 30, 2019 and December 31, 2018, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated loss Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Treasury stock, at cost; 249,481 and 223,040 shares of Class A common stock as of September 30, 2019 and December 31, 2018, respectively Treasury Stock, Value Total equity before noncontrolling interest Stockholders' Equity Attributable to Parent Noncontrolling interest Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity 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 Operating Leases, Future Minimum Payments Due Cash and cash equivalents Restricted cash - current Cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Subsequent Events Subsequent Events [Text Block] Equity Method Investments and Joint Ventures [Abstract] Unconsolidated Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Energy derivative Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Recurring Measurement Basis Fair Value, Recurring [Member] 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] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balances, beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Total gain (loss) included in electricity sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Balances, end of period Debt Disclosure [Abstract] Schedule of Long Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Reconciliation of Interest Expense Interest expense components [Table Text Block] Interest expense components [Table Text Block] Schedule of Convertible Debt Convertible Debt [Table Text Block] Related Party Transactions [Abstract] Related Party Transactions Receivable and Payable Related Party Transactions Receivable and Payable [Table Text Block] Related Party Transactions Receivable and Payable [Table Text Block] Related Party Revenue and Expenses Included in Consolidated Statements of Operations Schedule of Related Party Transactions [Table Text Block] Related Party Transactions Purchase Agreements Related Party Transactions Purchase Agreements [Table Text Block] Related Party Transactions Purchase Agreements [Table Text Block] Computations of Class A Basic and Diluted Earnings (Loss) per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Basis of Presentation and Principles of Consolidation Consolidation, Policy [Policy Text Block] Unaudited Interim Financial Information Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Leases Lessee, Leases [Policy Text Block] Sales Tax Receivable Sales Tax Receivable, Policy [Policy Text Block] Sales Tax Receivable, Policy [Policy Text Block] Development Expenses Development Expense, Contingent Consideration, Policy [Policy Text Block] Development Expense, Contingent Consideration, Policy [Policy Text Block] Recently Adopted and Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Commitments and Contingencies Disclosure [Abstract] Other Commitments [Table] Other Commitments [Table] Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Measurement Input, Discount Rate Measurement Input, Discount Rate [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Collectibility of Receivables Collectibility of Receivables [Member] Interest in Western Interconnect by Third Party Interest in Western Interconnect by third party [Member] Interest in Western Interconnect by third party [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Panhandle 2 Panhandle Two [Member] Panhandle Two [Member] Broadview Project Broadview Project [Member] Broadview Project [Member] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Turbine Manufacturer Turbine Manufacturer [Member] Turbine Manufacturer [Member] Power Sale Agreements Power Sale Agreements [Member] Power Sale Agreements [Member] Project Finance Agreements Project Finance Agreements [Member] Project Finance Agreements [Member] Pacific Gas & Electric Pacific Gas & Electric [Member] Pacific Gas & Electric [Member] Contingent Consideration by Type [Axis] Contingent Consideration by Type [Axis] Contingent Consideration Type [Domain] Contingent Consideration Type [Domain] Continued Operation Of Broadview Continued Operation Of Broadview [Member] Continued Operation Of Broadview [Member] Continued Operation Of Grady Continued Operation Of Grady [Member] Continued Operation Of Grady [Member] Other Commitments [Line Items] Other Commitments [Line Items] Land agreements, rent expense Land Agreements, Rent Expense Land Agreements, Rent Expense Letters of credit issued Letters of Credit Outstanding, Amount Loss contingency accrual Loss Contingency Accrual Contingent liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability Ownership percentage Ownership Percentage Ownership Percentage Contingent consideration, measurement input Business Combination, Contingent Consideration, Liability, Measurement Input Contingent liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Contingent Liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Contingent Liability Cash paid for contingent consideration Payment for Contingent Consideration Liability, Financing Activities Pre-petition invoice amount Bankruptcy Claims, Amount of Claims Filed Related Party Transactions Related Party Transactions Disclosure [Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Development Expense Development Expense, Contingent Consideration [Member] Development Expense, Contingent Consideration [Member] Other Income (Expense), Net Other Income (Expense) [Member] Other Income (Expense) [Member] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Contingent Consideration Contingent Consideration Liability [Member] Contingent Consideration Liability [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balances, beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Purchase Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Total loss included in earnings Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Foreign currency translation adjustments recognized in accumulated OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) Settlement Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Balances, end of period Remaining performance obligation Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Remaining performance obligation, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Electricity sales Electricity Sales [Member] Electricity Sales [Member] Electricity sales under PSA Electricity Sales Under PSA [Member] Electricity Sales Under PSA [Member] Electricity sales to market Electricity Sales To Market [Member] Electricity Sales To Market [Member] Stand-alone REC sales Renewable Energy Credits Sales [Member] Renewable Energy Credits Sales [Member] Other revenue from contracts with customers Other Revenue [Member] Other Revenue [Member] Related party management service fees Related Party Management Service Fees [Member] Related Party Management Service Fees [Member] Other electricity sales Other Electricity Sales [Member] Other Electricity Sales [Member] Other revenue Other Revenue, Related Party [Member] Other Revenue, Related Party [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total revenue from contracts with customers Revenue from Contract with Customer, Excluding Assessed Tax Total revenue Revenues Deferred financing costs, current, accumulated amortization Accumulated Amortization of Debt Issuance Costs, Line of Credit Arrangements Class A common stock, shares authorized (in Shares) Common Stock, Shares Authorized Class A common stock, shares outstanding (in Shares) Common Stock, Shares, Outstanding Treasury stock (in Shares) Treasury Stock, Shares Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other current assets Other Current Assets [Member] Other current liabilities Other Current Liabilities [Member] Contingent liabilities, current Contingent Liabilities, Current [Member] Contingent Liabilities, Current [Member] Contingent liabilities Contingent Liabilities, Noncurrent [Member] Contingent Liabilities, Noncurrent [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Due from related parties Due from Related Parties Due to related parties Due to Related Parties Depreciation expense related to property, plant and equipment Depreciation Schedule of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate, Other and Eliminations Corporate And Reconciling Items [Member] Corporate And Reconciling Items [Member] Reconciling Amounts Segment Reconciling Items [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Operating Business Operating Business [Member] Operating Business [Member] Development Investment Development Investment [Member] Development Investment [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Depreciation, amortization and accretion Cost, Depreciation and Amortization Impairment expense Asset Impairment Charges Operating income (loss) Operating Income (Loss) Earnings (loss) in unconsolidated investments Income (Loss) from Equity Method Investments Interest expense Interest Expense Income tax provision Income Tax Expense (Benefit) Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Adjusted EBITDA Adjusted EBITDA Adjusted EBITDA Capital expenditures Payments to Acquire Productive Assets Loss related to portion of loss of Pattern Development Income (Loss) from Subsidiaries, Net of Tax Income (Loss) From Equity Method Investments, Portion Attributable To Intra-Entities Income (Loss) From Equity Method Investments, Portion Attributable To Intra-Entities Income (Loss) From Equity Method Investments, Portion Attributable To Intra-Entities Revenue Equity Method Investment, Summarized Financial Information, Revenue Cost of revenue Equity Method Investment, Summarized Financial Information, Cost of Sales Operating expenses Equity Method Investment Summarized Financial Information Operating Expenses Equity Method Investment Summarized Financial Information Operating Expenses Other expense Equity Method Investment Summarized Financial Information Other Income Expenses Equity method investment summarized financial information other income (expenses). Net income (loss) Equity Method Investment, Summarized Financial Information, Net Income (Loss) Net loss Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Change in foreign currency translation, net of zero tax impact for all periods presented Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Cash flow hedge activity: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Change in unrealized gain (loss) on cash flow hedges, net of tax impact of $(1), $(2), $(7) and $(1), respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Reclassifications to net loss, net of tax impact of less than $1 for all periods presented Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Total change in cash flow hedge activity Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Other comprehensive income (loss) related to equity method investee net of tax impact of less than $(1), ($1), $(2) and ($1), respectively Other Comprehensive Income Loss Share Equity Method Investee Net Of Tax Proportionate share of equity investee's other comprehensive (loss) income activity, net of tax benefit (provision). Total other comprehensive gain (loss), net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive loss attributable to noncontrolling interests, net of tax impact of less than $1 for all periods presented Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income (loss) attributable to Pattern Energy Comprehensive Income (Loss), Net of Tax, Attributable to Parent Earnings Per Share Reconciliation [Abstract] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Restricted stock awards Restricted Stock [Member] Restricted stock units Restricted Stock Units (RSUs) [Member] Convertible senior notes Convertible Debt Securities [Member] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Antidilutive securities excluded from computation of earnings per share (less than in 2018) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Numerator for basic and diluted EPS: Earnings Per Share, Basic, Two Class Method [Abstract] Net earnings (loss) attributable to controlling interest Net Income (Loss) Attributable to Parent Numerator for basic EPS - net income (loss) attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Add back convertible senior notes interest Interest on Convertible Debt, Net of Tax Numerator for diluted EPS - net income (loss) attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Diluted Denominator for EPS: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Class A common stock - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Add dilutive effect (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Class A common stock - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Calculation of basic and diluted earnings (loss) per share: Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Dividends declared per Class A common share (in dollars per share) ERP Purchase ERP Purchase [Member] ERP Purchase [Member] Pattern Energy Group LP Affiliated Entity [Member] Investment in related party Investment in Related Party Investment in Related Party Equity method investment, aggregate cost Equity Method Investment, Aggregate Cost Percentage of Ownership Equity Method Investment, Ownership Percentage Supplemental Balance Sheet Information Assets And Liabilities, Lessee [Table Text Block] Assets And Liabilities, Lessee [Table Text Block] Schedule of Maturities of Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Schedule of Lease Cost Lease, Cost [Table Text Block] Schedule of Estimated Future Commitments Related to Operating Leases and Land Agreements Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Segment Reporting Segment Reporting Disclosure [Text Block] Other revenue Project expense Project Expense [Member] Project Expense [Member] General and administrative General and Administrative Expense [Member] Related party general and administrative Related Party, General And Administrative Expense [Member] Related Party, General And Administrative Expense [Member] Management fees Revenue from Related Parties MSA reimbursement Related Party Transaction Reimbursement From Transactions With Related Party Related party transaction reimbursement from transactions with related party MSA costs Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Corporate Revolving Credit Facility Revolver credit facility [Member] Revolver credit facility [Member] Incremental Bank Loan Incremental Bank Loan [Member] Incremental Bank Loan [Member] 2020 Notes Convertible senior notes 2020 [Member] Convertible senior notes 2020 [Member] 2024 Notes Unsecured senior notes 2024 [Member] Unsecured senior notes 2024 [Member] Santa Isabel term loan Santa Isabel Term Loan [Member] Santa Isabel Term Loan [Member] Mont Sainte Marguerite-med term loan Mont Sainte Marguerite-Med Term Loan [Member] Mont Sainte Marguerite-Med Term Loan [Member] Mont Sainte Marguerite-long term loan Mont Sainte Marguerite-Long Term Loan [Member] Mont Sainte Marguerite-Long Term Loan [Member] Gulf Wind Promissory Note Gulf Wind Promissory Note [Member] Gulf Wind Promissory Note Japan Credit Facility Japan Credit Facility [Member] Japan Credit Facility [Member] Ocotillo commercial term loan Ocotillo Commercial Term Loan [Member] Ocotillo Commercial Term Loan [Member] St. Joseph term loan St Joseph Credit Agreement [Member] St Joseph Credit Agreement [Member] Western Interconnect term loan Western Interconnect [Member] Western Interconnect [Member] Meikle term loan Meikle Wind Energy Limited Partnership [Member] Meikle Wind Energy Limited Partnership [Member] Futtsu term loan Futtsu Term Loan [Member] Futtsu Term Loan [Member] Ohorayama term loan Ohorayama Term Loan [Member] Ohorayama Term Loan [Member] Tsugaru Construction Loan Tsugaru Construction Loan [Member] Tsugaru Construction Loan [Member] Tsugaru Holdings Loan Agreement Tsugaru Holdings Loan [Member] Tsugaru Holdings Loan [Member] Hatchet Ridge financing lease obligation Hatchet Ridge Term Loan [Member] Hatchet Ridge Term Loan [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term debt, gross Long-term Debt, Gross Unamortized discount, net Debt Instrument, Unamortized Discount (Premium), Net Unamortized financing costs Debt Issuance Costs, Net Total debt, net Long-term Debt Contractual Interest Rate Debt Instrument, Interest Rate, Stated Percentage Effective Interest Rate Debt Instrument, Interest Rate, Effective Percentage Revolving credit facility, current Revolving credit facility Long-term debt, less current portion Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] PSP Investments PSP Investments [Member] PSP Investments [Member] Belle River Belle River [Member] Belle River [Member] North Kent North Kent [Member] North Kent [Member] South Kent South Kent [Member] South Kent [Member] Pattern Belle River GP Holdings Inc. Pattern Belle River GP Holdings Inc. [Member] Pattern Belle River GP Holdings Inc. [Member] Pattern North Kent Wind 1 GP Holdings Inc. Pattern North Kent Wind 1 GP Holdings Inc. [Member] Pattern North Kent Wind 1 GP Holdings Inc. [Member] New JV LP New JV LP [Member] New JV LP [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Percentage of ownership Amount paid to acquire equity method investment Payments to Acquire Equity Method Investments Loan receivable incurred Equity Method Investment, Loan Receivable Acquired Equity Method Investment, Loan Receivable Acquired Basis difference Equity Method Investment, Difference Between Carrying Amount and Underlying Equity PPA of project (in years) Long Term Energy Sale Time Period Long Term Energy Sale Time Period Right to contribute, maximum amount Equity Method Investment, Right To Contribute, Maximum Amount Equity Method Investment, Right To Contribute, Maximum Amount Gains on distributions from unconsolidated investments Equity Method Investment, Gain (Loss) On Distributions Equity Method Investment, Gain (Loss) On Distributions Suspended equity earnings Equity Method Investment, Suspended Equity Income (Loss) Equity Method Investment, Suspended Equity Income (Loss) Amortization of basis difference for equity method investment Amortization of basis difference for equity method investment Amortization of basis difference for equity method investment Financial Assets and Liabilities Required Fair Value Measurement on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Reconciliation of Energy Derivative Contract Measured at Fair Value Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value Measurements, Recurring Level 3, Valuation Techniques Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Carrying Amounts and Fair Values of Company's Financial Liabilities Financial Instruments Not Measured At Fair Value Table [Table Text Block] Financial Instruments Not Measured At Fair Value Table [Table Text Block] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Interest rate derivatives Interest Rate Contract [Member] Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Gain on derivatives Gain (Loss) on Interest Rate Derivative Instruments Not Designated as Hedging Instruments Electricity sales Gain (Loss) on Price Risk Derivative Instruments Not Designated as Hedging Instruments Gain on derivatives Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Logan's Gap Logan's Gap [Member] Logan's Gap [Member] Panhandle 1 Panhandle One [Member] Panhandle One [Member] Post Rock Post Rock [Member] Post Rock [Member] Amazon Wind Amazon Wind Farm Flower Ridge [Member] Amazon Wind Farm Flower Ridge [Member] Meikle Meikle [Member] Meikle [Member] Stillwater Stillwater [Member] Stillwater [Member] Belle River Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Interest expense Interest Expense [Member] Gain on derivatives Gain (Loss) on Derivative Instruments [Member] Gains (losses) recognized in accumulated OCI Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Gains (losses) recognized in accumulated OCI Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Gains (losses) reclassified from accumulated OCI Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, 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 Gain recognized in interest expense Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net Leases Lessee, Operating Leases [Text Block] Acquisitions Business Combination Disclosure [Text Block] Interest expense, net of interest income Interest Expense, Net of Interest Income [Member] Interest Expense, Net of Interest Income [Member] Income tax provision Income Tax Expense (Benefit) [Member] Income Tax Expense (Benefit) [Member] Depreciation, amortization and accretion Depreciation, Amortization And Accretion [Member] Depreciation, Amortization And Accretion [Member] Gain (loss) on derivatives Earnings (loss) in unconsolidated investments, net Unrealized gain (loss) on derivatives Unrealized Gain (Loss) on Derivatives, Excluding Equity Method Investments Unrealized Gain (Loss) on Derivatives, Excluding Equity Method Investments Impairment expense Adjustments for unconsolidated investments Equity Method Investment, Adjustments Equity Method Investment, Adjustments Other Other Expense Other Expense Interest expense, net of interest income Interest Revenue (Expense), Net Depreciation, amortization and accretion Depreciation, Amortization And Accretion From EBITDA Calculation Depreciation, Amortization And Accretion From EBITDA Calculation Net loss before income tax Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax provision Net loss Summary of Accumulated Other Comprehensive Loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Number of renewable energy projects with ownership interests held Number Of Renewable Energy Projects With Ownership Interests Held Number Of Renewable Energy Projects With Ownership Interests Held Schedule of Projects Accounted under Equity Method of Accounting Equity Method Investments [Table Text Block] Schedule of Aggregate Operating Results of Unconsolidated Investments Schedule Of Aggregate Operating Results Of Unconsolidated Investments [Table Text Block] Schedule of Aggregate Operating Results of Unconsolidated Investments [Table Text Block] Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Debt Debt Disclosure [Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Schedule of Balances of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Notional Amount of Outstanding Derivative Contracts [Table] Notional Amount of Outstanding Derivative Contracts [Table] Notional Amount of Outstanding Derivative Contracts [Table] Undesignated Derivative Instruments Notional Amount of Outstanding Derivative Contracts [Line Items] Notional Amount of Outstanding Derivative Contracts [Line Items] [Line Items] for Notional Amount of Outstanding Derivative Contracts [Table] Notional amount Derivative, Notional Amount Nonmonetary notional amount Derivative, Nonmonetary Notional Amount Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Discontinued Operations and Disposal Groups [Abstract] Divested Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Reconciliation of Operating Profit (Loss) from Segments to Consolidated Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Income Statement [Abstract] Statement [Table] Statement [Table] Other revenue Statement [Line Items] Statement [Line Items] Revenue: Revenues [Abstract] Total revenue Cost of revenue: Cost of Revenue [Abstract] Project expense Utilities Operating Expense, Maintenance and Operations Transmission costs Cost, Direct Material Total cost of revenue Cost of Revenue Gross profit (loss) Gross Profit Operating expenses: Operating Expenses [Abstract] General and administrative General and Administrative Expense Development expenses Development Expense, Contingent Consideration Development Expense, Contingent Consideration Related party general and administrative Total operating expenses Operating Expenses Other income (expense): Nonoperating Income (Expense) [Abstract] Interest expense Gain on derivatives Unrealized Gain (Loss) on Derivatives Net gain (loss) on transactions Nonoperating Gains (Losses) Other expense, net Other Nonoperating Income (Expense) Total other expense Nonoperating Income (Expense) Net loss attributable to noncontrolling interest Net income (loss) attributable to Pattern Energy Weighted-average number of common shares outstanding Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Diluted (in shares) Net income (loss) per share attributable to Pattern Energy Business Acquisition, Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Term Conversion Of Tsugaru Construction Loan Term Conversion Of Tsugaru Construction Loan [Member] Term Conversion Of Tsugaru Construction Loan [Member] Asset, change in unrealized gain (loss) Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Additional earn-out payment possible Business Combination, Contingent Consideration Arrangements, Additional Payment Business Combination, Contingent Consideration Arrangements, Additional Payment Increase in additional earn-out payment Business Combination, Contingent Consideration Arrangements, Additional Payment, Increase Per Criteria Business Combination, Contingent Consideration Arrangements, Additional Payment, Increase Per Criteria Decrease in additional earn-out payment Business Combination, Contingent Consideration Arrangements, Additional Payment, Decrease Per Criteria Business Combination, Contingent Consideration Arrangements, Additional Payment, Decrease Per Criteria Contingent consideration Business Combination, Contingent Consideration, Liability Development expenses Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Transmission wheeling revenue, period Projected Transmission Wheeling Revenue, Period Projected Transmission Wheeling Revenue, Period Contingent consideration paid Payment for Contingent Consideration Liability, Operating Activities Liability, change in unrealized gain (loss) Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss) Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Convertible debt Convertible Debt [Member] Principal Debt Instrument, Face Amount Unamortized debt discount Debt Instrument, Unamortized Discount Unamortized financing costs Unamortized Debt Issuance Expense Carrying value of convertible senior notes Convertible Debt Carrying value of the equity component Debt Instrument, Convertible, Carrying Amount of Equity Component Equity component of convertible debt issuance costs Equity Component of Convertible Debt Issuance Costs Equity Component of Convertible Debt Issuance Costs Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Measurement Input, Commodity Forward Price Measurement Input, Commodity Forward Price [Member] Measurement Input, Annual Energy Production Loss Measurement Input, Annual Energy Production Loss [Member] Measurement Input, Annual Energy Production Loss [Member] Measurement Input, Deferred Purchase Price Measurement Input, Deferred Purchase Price [Member] Measurement Input, Deferred Purchase Price [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] Level 3 Fair Value, Inputs, Level 3 [Member] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Discounted Cash Flow Valuation Technique, Discounted Cash Flow [Member] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Energy derivative Contingent consideration Energy derivative, measurement input Derivative Asset, Measurement Input Corporate-level interest and commitment fees incurred Interest And Commitment Fees Incurred, Corporate Level Interest And Commitment Fees Incurred, Corporate Level Project-level interest and commitment fees incurred Interest And Commitment Fees Incurred, Project Level Interest And Commitment Fees Incurred, Project Level Capitalized interest, commitment fees, and letter of credit fees Capitalized Interest Commitment Fees And Letter Of Credit Fees Capitalized Interest Commitment Fees And Letter Of Credit Fees Amortization of debt discount/premium, net Amortization of Debt Discount (Premium) Amortization of financing costs Amortization Of Debt Issuance Costs And Construction In Process Amortization Of Debt Issuance Costs And Construction In Process Interest expense Common Stock Common Stock [Member] Treasury Stock Treasury Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Accumulated Income (Loss) Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Total Parent [Member] Noncontrolling Interest Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Common Stock, Shares, Issued Beginning balance Issuance of Class A common stock under equity incentive award plan, shares Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture Issuance of Class A common stock under equity incentive award plan, net Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture Forfeitures of Class A common stock under equity incentive award plan (in shares) Shares Issued, Shares, Share-based Payment Arrangement, Forfeited Forfeitures of Class A common stock under equity incentive award plan Shares Issued, Value, Share-based Payment Arrangement, Forfeited Repurchase of shares for employee tax withholding, shares Stock Repurchased During Period, Shares Repurchase of shares for employee tax withholding Stock Repurchased During Period, Value Stock-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Dividends declared Dividends Acquisitions Sale of subsidiaries Noncontrolling Interest, Decrease from Deconsolidation Contributions from noncontrolling interests Distributions to noncontrolling interests Other comprehensive loss, net of tax Ending balance (in shares) Ending balance Remaining maturities Derivative, Remaining Maturity AOCL to be reclassified within 12 months Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Statement of Cash Flows [Abstract] Operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation, amortization and accretion Depreciation, Amortization and Accretion, Net Loss (gain) on derivatives Unrealized Gain (Loss) on Derivatives and Commodity Contracts Stock-based compensation Share-based Payment Arrangement, Noncash Expense Deferred taxes Deferred Income Taxes and Tax Credits (Earnings) losses in unconsolidated investments, net Non Cash Income Loss From Equity Method Investments Non Cash Income Loss From Equity Method Investments Distributions from unconsolidated investments Proceeds from Equity Method Investment, Distribution Other reconciling items Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Counterparty collateral asset Increase (Decrease) Cash Collateral from Counterparties Trade receivables Increase (Decrease) in Accounts Receivable Other current assets Increase (Decrease) in Other Current Assets Other assets (non-current) Increase (Decrease) in Other Noncurrent Assets Advanced lease revenue Increase (Decrease) in Leasing Receivables Accounts payable and other accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Counterparty collateral liability Increase (decrease) in liability to return cash collateral Increase (decrease) in liability to return cash collateral to derivative counterparty Contingent liabilities Other current liabilities Increase (Decrease) in Other Current Liabilities Other long-term liabilities Increase Decrease In Long Term Liabilities Increase decrease in long term liabilities. 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] Cash paid for acquisitions and investments, net of cash and restricted cash acquired Payments to Acquire Businesses, Net of Cash Acquired Proceeds from sale of investments, net of cash and restricted cash distributed Proceeds from Sale, Maturity and Collection of Investments Distributions from unconsolidated investments Proceeds from Equity Method Investment, Distribution, Return of Capital Other assets Payments for (Proceeds from) Other Investing Activities Net cash 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 Payments of Dividends Capital contributions - noncontrolling interest Proceeds from Noncontrolling Interests Capital distributions - noncontrolling interest Payments to Noncontrolling Interests Payment for financing fees Payments of Financing Costs Proceeds from long-term debt and other Proceeds from Issuance of Long-term Debt Repayment of long-term debt and other Repayments of Long-term Debt Proceeds from short-term debt Proceeds from Short-term Debt Repayment of short-term debt Repayments of Short-term Debt Cash paid for contingent consideration Payment for termination of designated derivatives Payments for Derivative Instrument, Financing Activities Other financing activities Proceeds from (Payments for) Other Financing Activities Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Net change in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Supplemental disclosures Supplemental Cash Flow Elements [Abstract] Cash payments for income taxes Income Taxes Paid Cash payments for interest expense Interest Paid, Excluding Capitalized Interest, Operating Activities Schedule of non-cash activities Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Change in property, plant and equipment Increase Decrease In Property Plant And Equipment Reclasses within capitalized development costs, CIP and property. Accrual of equity issuance costs Equity Issuance Costs Paid In Prior Period Related to Current Period Offerings Equity Issuance Costs Paid In Prior Period Related to Current Period Offerings Noncontrolling Interests By Project Noncontrolling Interests By Project [Table Text Block] [Table Text Block] for Noncontrolling Interests By Project [Table] Summary of Noncontrolling Interest Balances Noncontrolling Interest Table [Table Text Block] Noncontrolling Interest Table [Table Text Block] Cash consideration net of acquired cash Payments to Acquire Businesses, Gross Debt Assumed Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Current Liabilities, Long-term Debt, Including Accrued Interest Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Current Liabilities, Long-term Debt, Including Accrued Interest Contingent Consideration Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Assets, Fair Value Disclosure [Abstract] Assets, Fair Value Disclosure [Abstract] Assets Assets, Fair Value Disclosure Liabilities, Fair Value Disclosure [Abstract] Liabilities, Fair Value Disclosure [Abstract] Derivative liability (less than $1 million for foreign currency forward contracts in September 30,2019) Derivative Liability Liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure Reconciliation of Cash and Cash Equivalents and Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Reconciliation of Cash and Cash Equivalents and Restricted Cash Cash, Cash Equivalents and Investments [Table Text Block] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] El Arrayan SPA El Arrayan SPA [Member] El Arrayan SPA [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued Operations, Disposed of by Sale Discontinued Operations, Disposed of by Sale [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Distance of facility from Santiago Disposal Group, Including Discontinued Operation, Distance Of Facility From Santiago, Chile Disposal Group, Including Discontinued Operation, Distance Of Facility From Santiago, Chile Generating capacity Disposal Group, Including Discontinued Operation, Generating Capacity Disposal Group, Including Discontinued Operation, Generating Capacity Cash proceeds Proceeds from Divestiture of Businesses Impairment loss Discontinued Operation, Provision for Loss (Gain) on Disposal, Net of Tax Grand Grand Renewable Wind L P [Member] Grand Renewable Wind L P [Member] Armow Armow [Member] Armow [Member] Pattern Development PEGH2 [Member] PEGH2 [Member] Remainder of 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 payment Lessee, Operating Lease, Liability, Payments, Due Less imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Total Cover page. 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Equity Investee’s OCI Accumulated Proportionate Share Of Equity Investees Other Comprehensive Income [Member] Accumulated Proportionate Share Of Equity Investees Other Comprehensive Income [Member] AOCI AOCI Including Portion Attributable to Noncontrolling Interest [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward] Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from accumulated other comprehensive loss Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Revenue recognized on contract with customer, liability (less than for 3 months ended) Contract with Customer, Liability, Revenue Recognized Operating lease right-of-use assets Operating lease liabilities, current Operating Lease, Liability, Current Operating lease liabilities Operating Lease, Liability, Noncurrent Total operating lease liabilities Accumulated Other Comprehensive Loss Comprehensive Income (Loss) Note [Text Block] Line of Credit Facility [Table] Line of Credit Facility [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Bridge Loan Bridge Loan [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Tsugaru Credit Facility Tsugaru Credit Facility [Member] Tsugaru Credit Facility [Member] Debt Service Reserve Account LC Debt Service Reserve Account LC [Member] Debt Service Reserve Account LC [Member] O&M Reserve Account LC O&M Reserve Account LC [Member] O&M Reserve Account LC [Member] Tsugaru Letter Of Credit Facilities Tsugaru Letter Of Credit Facilities [Member] Tsugaru Letter Of Credit Facilities [Member] Japanese Consumption Tax Facility Japanese Consumption Tax Facility [Member] Japanese Consumption Tax Facility [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Federal Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] Eurodollar Eurodollar [Member] Base Rate Base Rate [Member] LIBOR London Interbank Offered Rate (LIBOR) [Member] Tokyo Interbank Offered Rate (TIBOR) Tokyo Interbank Offered Rate (TIBOR) [Member] Tokyo Interbank Offered Rate (TIBOR) [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Debt term Debt Instrument, Term Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Line of credit term loan Long-term Line of Credit Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Interest rate Debt Instrument Basis Spread On Variable Rate Interest Period Debt Instrument Basis Spread On Variable Rate Interest Period Contractual interest rate Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Debt term, following conversion Debt Instrument, Term, Following Conversion Debt Instrument, Term, Following Conversion Unused capacity, commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long-term debt, including current portion as reflected on balance sheets Fair value, long-term debt, including current portion Long-term Debt, Fair Value