Entity Central Index Key Operating real estate investment property net. Third party management expenses. Net gain (loss) on sale of undepreciated real estate. Net gain (loss) on real estate venture transactions including real estate venture formation. Straight-line rent excluding rent termination fee. Ground rent expense. Net gain (loss) on real estate venture transactions. Income (loss) from real estate ventures, net of distributions. Payments to redevelop real estate - Capital expenditures to redevelop real estate. Advances for purchase of tenant assets, net of repayments. Payments on account of employee tax withholdings on share based awards. Partner distributions from consolidated real estate venture. Equity Method Investment Summarized Financial Information Operating expenses. Equity Method Investment Summarized Financial Information Interest expense net. Equity Method Investment Summarized Financial Information Depreciation and amortization. Equity method investment summarized financial information loss on extinguishment of debt. Equity method investment summarized financial information of net income loss before adjustments. Equity method investment summarized financial information on basis adjustments and other. Total unsecured indebtedness. Long term-debt maturities repayments of principal Net income loss attributable to noncontrolling interest diluted. Document And Entity Information. Document And Entity Information [Abstract] Document Information [Table] Document Information [Table] Consolidated Entities Consolidated Entities [Axis] Consolidated Entities Consolidated Entities [Domain] BRANDYWINE OPERATING PARTNERSHIP, L.P. Subsidiaries [Member] Document Information [Line Items] Document Information [Line Items] Entity Registrant Name Entity Registrant Name Trading Symbol Trading Symbol Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Shell Company Entity Shell Company Title of 12(b) Security Security12b Title Security Exchange Name Security Exchange Name Entity File Number Entity File Number Entity Incorporation, State or Country Code Entity Incorporation State Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address Address Line1 Entity Address, Address Line Two Entity Address Address Line2 Entity Address, City or Town Entity Address City Or Town Entity Address, State or Province Entity Address State Or Province Entity Address, Postal Zip Code Entity Address Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Document Quarterly Report Document Quarterly Report Document Transition Report Document Transition Report Deferred compensation payable in common stock. Statement Of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] ASSETS Assets [Abstract] Real estate investments: Real Estate Investments [Abstract] Operating properties Investment Building And Building Improvements Accumulated depreciation Real Estate Investment Property Accumulated Depreciation Right of use asset - operating leases, net Operating Lease Right Of Use Asset Operating real estate investments, net Operating Real Estate Investment Property Net Construction-in-progress Development In Process Land held for development Land Available For Development Prepaid leasehold interests in land held for development, net Prepaid Expense Current And Noncurrent Total real estate investments, net Real Estate Investment Property Net Assets held for sale, net Assets Of Disposal Group Including Discontinued Operation Cash and cash equivalents Cash And Cash Equivalents At Carrying Value Accounts receivable, net of allowance of $284 and $1,653 as of June 30, 2019 and December 31, 2018, respectively Accounts Receivable Net Accrued rent receivable, net of allowance of $11,009 and $11,266 as of June 30, 2019 and December 31, 2018, respectively Deferred Rent Receivables Net Investment in Real Estate Ventures Real Estate Investments Joint Ventures Deferred costs, net Deferred Costs Current And Noncurrent Intangible assets, net Finite Lived Intangible Assets Net Other assets Other Assets Total assets Assets LIABILITIES AND EQUITY Liabilities And Stockholders Equity [Abstract] Mortgage notes payable, net Secured Debt Unsecured credit facility Line Of Credit Unsecured term loan, net Unsecured Debt Unsecured senior notes, net Senior Notes Accounts payable and accrued expenses Accounts Payable And Accrued Liabilities Current And Noncurrent Distributions payable Dividends Payable Current And Noncurrent Deferred income, gains and rent Contract With Customer Liability Acquired lease intangibles, net Below Market Lease Net Lease liability - operating leases Operating Lease Liability Other liabilities Other Liabilities Total liabilities Liabilities Commitments and contingencies Commitments And Contingencies Redeemable limited partnership units at redemption value; 982,871 issued and outstanding as of March 31, 2019 and December 31, 2018 Temporary Equity Carrying Amount Including Portion Attributable To Noncontrolling Interests Equity: Equity [Abstract] Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 400,000,000; 176,197,883 and 176,873,324 issued and outstanding as of June 30, 2019 and December 31, 2018, respectively Common Stock Value Additional paid-in-capital Additional Paid In Capital Deferred compensation payable in common shares Deferred Compensation Payable In Common Stock Common shares in grantor trust, 1,113,450 and 977,120 issued and outstanding as of June 30, 2019 and December 31, 2018, respectively Common Stock Held In Trust General Partnership Capital; 176,001,580 and 176,873,324 units issued and outstanding as of March 31, 2019 and December 31, 2018, respectively General Partners Capital Account Cumulative earnings Cumulative Earnings Deficit Accumulated other comprehensive income Accumulated Other Comprehensive Income Loss Net Of Tax Total Brandywine Operating Partnership, L.P.'s equity Partners Capital Cumulative distributions Cumulative Dividends Total Brandywine Realty Trust's equity Stockholders Equity Noncontrolling interests Minority Interest Non-controlling interest - consolidated real estate ventures Partners Capital Attributable To Noncontrolling Interest Total beneficiaries' equity Stockholders Equity Including Portion Attributable To Noncontrolling Interest Total partners' equity Partners Capital Including Portion Attributable To Noncontrolling Interest Total liabilities and beneficiaries' equity Liabilities And Stockholders Equity Allowance for doubtful accrued rent receivable. Common shares in grantor trust issued and outstanding. Accounts receivable, allowance Allowance For Doubtful Accounts Receivable Accrued rent receivable, allowance Allowance For Doubtful Accrued Rent Receivable Common Stock, Par or Stated Value Per Share (USD per share) Common Stock Par Or Stated Value Per Share Common Stock, Shares Authorized Common Stock Shares Authorized Common Stock, Shares, Issued and Outstanding Common Stock Shares Outstanding Common Shares in Grantor Trust, Issued and Outstanding Common Shares In Grantor Trust Issued And Outstanding Income Statement [Abstract] Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] Rents. Rents [Member] Rents [Member] Third party management revenue. Third Party Management Fees, Labor Reimbursement and Leasing [Member] Third Party Management Revenue [Member] Other [Member] Real Estate Other [Member] Revenue Revenues [Abstract] Lease revenue Operating Leases Income Statement Lease Revenue Service and other revenue Revenue From Contract With Customer Including Assessed Tax Total revenue Revenues Operating expenses Costs And Expenses [Abstract] Property operating expenses Direct Costs Of Leased And Rented Property Or Equipment Real estate taxes Real Estate Tax Expense Third party management expenses Third Party Management Expenses Depreciation and amortization Depreciation And Amortization General and administrative expenses General And Administrative Expense Total operating expenses Costs And Expenses Gain on sale of real estate Gain Loss On Sale Of Properties [Abstract] Net loss on disposition of real estate Disposal Group Not Discontinued Operation Gain Loss On Disposal Net gain on sale of undepreciated real estate Net Gain Loss On Sale Of Undepreciated Real Estate Total gain on sale of real estate Gain Loss On Sale Of Properties Operating income Operating Income Loss Other income (expense): Nonoperating Income Expense [Abstract] Interest income Interest Income Other Interest expense Interest Expense Debt Interest expense - amortization of deferred financing costs Amortization Of Financing Costs Equity in loss of Real Estate Ventures Income Loss From Equity Method Investments Net gain on real estate venture transactions Net Gain Loss On Real Estate Venture Transactions Including Real Estate Venture Formation Net income before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income tax provision Income Tax Expense Benefit Net income Profit Loss Net income attributable to noncontrolling interests Net Income Loss Attributable To Noncontrolling Interest Net income attributable to non-controlling interests - consolidated real estate ventures Income Loss From Continuing Operations Attributable To Noncontrolling Entity Net income attributable to Brandywine Realty Trust Net Income Loss Net Income (Loss) Allocated to Limited Partners Net Income Loss Allocated To Limited Partners Dividends Preferred Stock Dividends Preferred Stock Preferred Stock Redemption Premium Preferred Stock Redemption Premium Nonforfeitable dividends allocated to unvested restricted shareholders Undistributed Earnings Loss Allocated To Participating Securities Basic Net income attributable to Common Shareholders of Brandywine Realty Trust Net Income Loss Available To Common Stockholders Basic Basic income per Common Share Income Loss From Continuing Operations Per Basic Share Diluted income per Common Share Income Loss From Continuing Operations Per Diluted Share Basic weighted average shares outstanding Weighted Average Number Of Shares Outstanding Basic Diluted weighted average shares outstanding Weighted Average Number Of Diluted Shares Outstanding Statement Of Income And Comprehensive Income [Abstract] Net income Comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Unrealized gain (loss) on derivative financial instruments Other Comprehensive Income Unrealized Gain Loss On Derivatives Arising During Period Net Of Tax Amortization of interest rate contracts Other Comprehensive Income Loss Reclassification Adjustment From A O C I On Derivatives Net Of Tax Comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Comprehensive income Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest Comprehensive income attributable to noncontrolling interest Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest Comprehensive income attributable to Brandywine Realty Trust Comprehensive Income Net Of Tax Noncontrolling interest, increase (decrease) from subsidiary equity issuance. Share issuance from/to deferred compensation plan shares. Share issuance from/to deferred compensation plan. Noncontrolling interest increase decrease from reallocation. Stock issued during period share redemption of limited partners units. Stock Issued during period value redemption of limited partners units. Share choice plan issuance shares. Statement Of Stockholders Equity [Abstract] Accumulated Other Comprehensive Income (Loss) [Member] Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock [Member] Common Stock [Member] Deferred Compensation, Share-based Payments [Member] Deferred Compensation Share Based Payments [Member] Additional Paid-in Capital [Member] Additional Paid In Capital [Member] Common stock held in trust. Common Stock In Grantor Trust [Member] Common Stock Held In Trust [Member] Cumulative Earnings [Member] Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) [Member] Accumulated Other Comprehensive Income [Member] Cumulative Distributions [Member] Accumulated Distributions In Excess Of Net Income [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Beginning Balance Beginning Balance, Shares Shares Issued Cumulative effect of accounting change Cumulative Effect On Retained Earnings Net Of Tax1 Other comprehensive income (loss) Issuance of Common Shares of Beneficial Interest Stock Issued During Period Value New Issues Issuance of Common Shares of Beneficial Interest, Shares Stock Issued During Period Shares Conversion Of Units Repurchase and retirement of Common Shares of Beneficial Interest Stock Repurchased And Retired During Period Value Repurchase and retirement of Common Shares of Beneficial Interest, Shares Stock Repurchased And Retired During Period Shares Issuance of partnership interest in consolidated real estate ventures Noncontrolling Interest Increase Decrease From Subsidiary Equity Issuance Distributions from consolidated real estate ventures Minority Interest Decrease From Distributions To Noncontrolling Interest Holders Redemption of LP Units Stock Issued During Period Value Redemption Of Limited Partners Units Redemption of LP Units, Shares Stock Issued During Period Share Redemption Of Limited Partners Units Share-based compensation activity Stock Issued During Period Value Share Based Compensation Share-based compensation activity, Shares Stock Issued During Period Shares Share Based Compensation Share Issuance from/(to) Deferred Compensation Plan Share Issuance From To Deferred Compensation Plan Share Issuance from/(to) Deferred Compensation Plan, Shares Share Issuance From To Deferred Compensation Plan Shares Share Choice Plan issuance Share Choice Plan Issuance Shares Reallocation of Noncontrolling interest Noncontrolling Interest Increase Decrease From Reallocation Distributions declared Dividends Common Stock Cash Ending Balance Ending Balance, Shares Distributions declared per Common Share Common Stock Dividends Per Share Declared Change in deferred income, gains and rent to the non-cash disposition of land. Change in investment in real estate ventures as a result of a disposition. Noncash or Part Noncash Asset Acquisition, Operating Real Estate Change In Intangible Assets Net Related To Noncash Acquisition Of Operating Property Change In Acquired Lease Intangibles Net Related To Noncash Acquisition Of Operating Property Noncash or part noncash acquisition, investments in joint venture. Change in capital expenditures financed through accounts payable. Change in capital expenditures financed through retention payable at period end. Reconciliation of cash cash equivalents and restricted cash. Statement Of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net income to net cash from operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Amortization of deferred financing costs Amortization of debt discount/(premium), net Amortization Of Debt Discount Premium Amortization of stock compensation costs Share Based Compensation Straight-line rent income Straight Line Rent Excluding Rent Termination Fee Amortization of acquired above (below) market leases, net Amortization Of Above And Below Market Leases Ground rent expense Ground Rent Expense Provision for doubtful accounts Provision For Doubtful Accounts Net gain on real estate venture transactions Net Gain Loss On Real Estate Venture Transactions Net gain on sale of interests in real estate Income from Real Estate Ventures, net of distributions Income Loss From Real Estate Ventures Net Of Distributions Income tax provision Changes in assets and liabilities: Increase Decrease In Operating Capital [Abstract] Accounts receivable Increase Decrease In Accounts Receivable Other assets Increase Decrease In Other Operating Assets Accounts payable and accrued expenses Increase Decrease In Accounts Payable And Accrued Liabilities Deferred income, gains and rent Increase Decrease In Contract With Customer Liability Other liabilities Increase Decrease In Other Operating Liabilities Net cash provided by operating activities Net Cash Provided By Used In Operating Activities Cash flows from investing activities: Net Cash Provided By Used In Investing Activities [Abstract] Acquisition of properties Payments To Acquire Real Estate Proceeds from the sale of properties Proceeds From Sale Of Property Plant And Equipment Proceeds from real estate venture sales Proceeds From Sale Of Equity Method Investments Issuance of mortgage note receivable Payments To Acquire Investments Proceeds from repayment of mortgage notes receivable Proceeds From Sale And Collection Of Mortgage Notes Receivable Capital expenditures for tenant improvements Payments For Tenant Improvements Capital expenditures for redevelopments Payments To Redevelop Real Estate Capital expenditures for developments Payments To Develop Real Estate Assets Advances for the purchase of tenant assets, net of repayments Advances To Tenant For Purchase Of Tenant Assets Investment in unconsolidated Real Estate Ventures Payments To Acquire Equity Method Investments Deposits for real estate Payments For Proceeds From Deposits On Real Estate Acquisitions Capital distributions from Real Estate Ventures Proceeds From Equity Method Investment Dividends Or Distributions Return Of Capital Leasing costs paid Payments For Leasing Costs Commissions And Tenant Improvements Net cash used in investing activities Net Cash Provided By Used In Investing Activities Cash flows from financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Repayments of mortgage notes payable Repayments Of Secured Debt Proceeds from credit facility borrowings Proceeds From Long Term Lines Of Credit Repayments of credit facility borrowings Repayments Of Long Term Lines Of Credit Proceeds from the exercise of stock options Proceeds From Stock Options Exercised Proceeds from the issuance of common shares Proceeds From Issuance Of Common Stock Shares used for employee taxes upon vesting of share awards Payments On Account Of Employee Tax Withholdings On Share Based Awards Partner contributions to consolidated real estate venture Proceeds From Partnership Contribution Partner distributions from consolidated real estate venture Partner Distributions From Consolidated Real Estate Venture Repurchase and retirement of common shares Payments For Repurchase Of Common Stock Distributions paid to shareholders Payments Of Dividends Distributions to noncontrolling interest Payments Of Dividends Minority Interest Net cash used in financing activities Net Cash Provided By Used In Financing Activities Decrease in cash and cash equivalents and restricted cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Excluding Exchange Rate Effect Cash and cash equivalents and restricted cash at beginning of year Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash and cash equivalents and restricted cash at end of period Reconciliation of cash and cash equivalents and restricted cash: Reconciliation Of Cash Cash Equivalents And Restricted Cash [Abstract] Cash and cash equivalents, beginning of period Restricted cash, beginning of period Restricted Cash And Cash Equivalents Cash and cash equivalents, end of period Restricted cash, end of period Supplemental disclosure: Supplemental Cash Flow Information [Abstract] Cash paid for interest, net of capitalized interest during the six months ended June 30, 2019 and 2018 of $1,465 and $1,577, respectively Interest Paid Net Cash paid for income taxes Income Taxes Paid Net Supplemental disclosure of non-cash activity: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Dividends and distributions declared but not paid Change in construction-in-progress related to non-cash disposition of land Construction In Progress Expenditures Incurred But Not Yet Paid Change in deferred income, gains and rent to the non-cash disposition of land Change In Deferred Income Gains And Rent To The Non Cash Disposition Of Land Change in investment in real estate ventures as a result of dispositions Change In Investment In Real Estate Ventures As Result Of Disposition Change in operating real estate related to a non-cash acquisition of an operating property Noncashor Part Noncash Asset Acquisition Operating Real Estate Change in intangible assets, net related to non-cash acquisition of an operating property Change In Intangible Assets Net Related To Noncash Acquisition Of Operating Property Change in acquired lease intangibles, net related to non-cash acquisition of an operating property Change In Acquired Lease Intangibles Net Related To Noncash Acquisition Of Operating Property Change in investments in joint venture related to non-cash acquisition of property Noncash Or Part Noncash Acquisition Investments In Joint Venture Acquired Change in mortgage notes payable related to acquisition of an operating property Noncash Or Part Noncash Acquisition Debt Assumed1 Change in capital expenditures financed through accounts payable at period end Change In Capital Expenditures Financed Through Accounts Payable Change in capital expenditures financed through retention payable at period end Change In Capital Expenditures Financed Through Retention Payable At Period End Capitalized interest Interest Paid Capitalized Redeemable Limited Partnership Units Issued and Outstanding Temporary Equity Shares Outstanding General Partners' Capital Account, Units Issued and Outstanding General Partners Capital Account Units Outstanding Partners capital account units repurchased and retired. Partners capital account repurchased and retired. Adjustment of redeemable partnership units to liquidation value at period end. Equity issuance costs and net proceeds from share issuances. Statement Of Partners Capital [Abstract] General Partner Capital [Member] Partner Type Of Partners Capital Account [Axis] Partner Type of Partners' Capital Account, Name Partner Type Of Partners Capital Account Name [Domain] General Partner Capital [Member] General Partner [Member] Beginning Balance Other comprehensive income (loss) Repurchase and retirement of LP units Partners Capital Account Repurchased And Retired Repurchase and retirement of LP units, Shares Partners Capital Account Units Repurchased And Retired Issuance of LP Units Equity Issuance Costs And Net Proceeds From Share Issuances Issuance of LP Units, Shares Partners Capital Account Units Sold In Public Offering Adjustment of redeemable partnership units to liquidation value at period end Adjustment Of Redeemable Partnership Units To Liquidation Value At Period End Distributions declared to general partnership unitholders Partners Capital Account Distributions Ending Balance Distributions to general partnership unitholders (USD per share) Distributions Per General Partnership Unit Outstanding Organization Consolidation And Presentation Of Financial Statements [Abstract] ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP Nature Of Operations Accounting Policies [Abstract] BASIS OF PRESENTATION Basis Of Presentation And Significant Accounting Policies [Text Block] Real Estate [Abstract] REAL ESTATE INVESTMENTS Real Estate Disclosure [Text Block] Equity Method Investments And Joint Ventures [Abstract] INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES Equity Method Investments Disclosure [Text Block] Intangible assets and liabilities disclosure. Goodwill And Intangible Assets Disclosure [Abstract] INTANGIBLE ASSETS AND LIABILITIES Intangible Assets And Liabilities Disclosure [Text Block] Debt Disclosure [Abstract] DEBT OBLIGATIONS Debt Disclosure [Text Block] Fair Value Disclosures [Abstract] FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value Disclosures [Text Block] Noncontrolling Interest [Abstract] LIMITED PARTNERS' NON-CONTROLLING INTERESTS IN THE PARENT COMPANY Minority Interest Disclosure [Text Block] Derivative Instruments And Hedging Activities Disclosure [Abstract] DERIVATIVE FINANCIAL INSTRUMENTS Derivative Instruments And Hedging Activities Disclosure [Text Block] Beneficiaries' Equity. BENEFICIARIES' EQUITY OF THE PARENT COMPANY Beneficiaries Equity [Text Block] PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP Partners Capital Notes Disclosure [Text Block] Segment Reporting [Abstract] SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] COMMITMENTS AND CONTINGENCIES Commitments And Contingencies Disclosure [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] Revision of previously issued financial statements, policy. Revision of Previously Issued Financial Statements Revision Of Previously Issued Financial Statements Policy Policy [Text Block] Adoptions of new accounting guidance. Adoptions of New Accounting Guidance Adoptions Of New Accounting Guidance Policy [Text Block] Lessor Accounting Lease Lessor Leases Policy [Text Block] Lessee Accounting Lease Lessee Leases Policy [Text Block] Fair Value Measurements Fair Value Measurement Policy Policy [Text Block] Recent Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Schedule of core portfolio of operating properties and excludes development and redevelopment properties under construction. Summary of Core Portfolio of Operating Properties and Excludes Development, Redevelopment and Held for Sale Schedule Of Core Portfolio Of Operating Properties And Excludes Development And Redevelopment Properties Under Construction Table [Text Block] Schedule of Revision of Previously Issued Financial Statements Schedule Of Error Corrections And Prior Period Adjustments [Text Block] Schedule of lessor future rentals on non-cancellable operating leases. Schedule Of Lease Payments on Non-Cancellable Leases Schedule Of Lessor Future Rentals On Non Cancellable Operating Leases Table [Text Block] Schedule Of Allocation Of Lease Revenue Recognized Between Fixed Contractual Payments And Variable Lease Payments Operating Lease Lease Income Table [Text Block] Summary of Operating Lease Cost Recognized Through Property Operating Expenses Lease Cost Table [Text Block] Gross Carrying Value of Operating Properties Schedule Of Real Estate Properties Table [Text Block] Summary of Gain on Sale for Each Land Parcel Schedule Of Disposal Groups Including Discontinued Operations Income Statement Balance Sheet And Additional Disclosures [Text Block] Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) Equity Method Investments [Text Block] Schedule of finite lived intangible assets and liabilities. Summary of Intangible Assets and Liabilities Schedule Of Finite Lived Intangible Assets And Liabilities Table [Text Block] Finite lived intangible assets and liabilities amortization expense table text block. Summary of Amortization for Intangible Assets and Liabilities Finite Lived Intangible Assets And Liabilities Amortization Expense Table [Text Block] Consolidated debt obligations Schedule Of Debt Table [Text Block] Schedule of Maturities of Long-term Debt Schedule Of Maturities Of Long Term Debt Table [Text Block] Schedule of Financial Instruments With Fair Values Different From Their Carrying Amount Fair Value By Balance Sheet Grouping [Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value [Text Block] Earnings Per Share (EPS), Basic and Diluted Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Real Estate Investments, Net Operating Income and Unconsolidated Real Estate Ventures of Reportable Segments Schedule Of Segment Reporting Information By Segment [Text Block] Reconciliation of Consolidated Net Income to Consolidated NOI Reconciliation Of Operating Profit Loss From Segments To Consolidated [Text Block] Lease Payments on Non-cancelable Leases Contractual Obligation Fiscal Year Maturity Schedule Table [Text Block] Organization of The Parent Company and The Operating Partnership. Organization of The Parent Company and The Operating Partnership. Organization Of Parent Company And Operating Partnership [Table] Organization Of Parent Company And Operating Partnership [Table] Ownership Ownership [Axis] Ownership Ownership [Domain] Brandywine operating partnership LP. Brandywine Operating Partnership LP [Member] Brandywine Operating Partnership L P [Member] Parent Company [Member] Parent Company [Member] Property, Plant and Equipment, Type Property Plant And Equipment By Type [Axis] Property, Plant and Equipment, Type Property Plant And Equipment Type [Domain] Leashold interest land. Leashold Interest Land [Member] Leashold Interest Land [Member] Disposal Group Classification Disposal Group Classification [Axis] Disposal Group Classification Disposal Group Classification [Domain] Land parcel one. Land Parcel One [Member] Land Parcel One [Member] Land parcel two. Land Parcel Two [Member] Land Parcel Two [Member] Assets Held-for-sale [Member] Disposal Group Heldforsale Not Discontinued Operations [Member] Management company subsidiaries. Wholly-owned Management Company Subsidiaries [Member] Management Company Subsidiaries [Member] Real Estate Property Ownership Real Estate Properties [Axis] Real Estate Properties Real Estate Properties [Domain] Wholly Owned Properties [Member] Wholly Owned Properties [Member] Partially Owned Properties [Member] Partially Owned Properties [Member] Organization of The Parent Company and The Operating Partnership [Line Items] Organization Of Parent Company And Operating Partnership [Line Items] Ownership in the Operating Partnership Minority Interest Ownership Percentage By Parent Number of Properties Number Of Real Estate Properties Net Rentable Square Feet Area Of Real Estate Property Schedule Of Real Estate Properties [Table] Schedule Of Real Estate Properties [Table] Mixed-use properties. Mixed-use Properties [Member] Mixed Use Properties [Member] Retail Properties [Member] Retail Site [Member] Core Properties [Member] Core Properties [Member] Core Properties [Member] Development projects. Development Projects [Member] Development Projects [Member] Redevelopment projects. Redevelopment Projects [Member] Redevelopment Projects [Member] Real Estate, Type of Property Mortgage Loans On Real Estate Description Type Of Property [Axis] Real Estate Mortgage Loans On Real Estate Name Property Type [Domain] Office Properties [Member] Office Building [Member] Real Estate Properties [Line Items] Real Estate Properties [Line Items] Rentable Square Feet Area of land held for development. Land held under available for sale Area of additional undeveloped parcels of land with option to purchase. Number of parcels of land. Lease agreement term. The amount of development that can be supported by undeveloped land Areas of land held for development Area Of Land Held For Development Land Held for Sale Land Held Under Available For Sale Area of Additional Undeveloped Parcels of Land With Option to Purchase Area Of Additional Undeveloped Parcels Of Land With Option To Purchase Number of Parcels Number Of Parcels Of Land Lease agreement term Lease Agreement Term Total Potential Development Capacity Potential Development Capacity Number of acquisitions for which adjustments have been made to correct related to errors of purchase price allocation. Basis of presentation. Schedule of basis of presentation. Schedule Of Basis Of Presentation [Table] Schedule Of Basis Of Presentation [Table] Adjustments for Error Corrections Error Corrections And Prior Period Adjustments Restatement By Restatement Period And Amount [Axis] Adjustments for Error Correction Adjustments For Error Correction [Domain] Error corrections and prior period adjustments. Error Corrections and Prior Period Adjustments [Member] Error Corrections And Prior Period Adjustments [Member] Reversal of the out of period adjustment. Reversal of Out of Period Adjustment [Member] Reversal Of Out Of Period Adjustment [Member] Reversal of out of period adjustment offset. Reversal of Out of Period Adjustment Offset [Member] Reversal Of Out Of Period Adjustment Offset [Member] Change in Accounting Estimate by Type Change In Accounting Estimate By Type [Axis] Change in Accounting Estimate, Type Change In Accounting Estimate Type [Domain] Uncollectible Leases. Uncollectible Leases [Member] Uncollectible Leases [Member] Disposal Group Name Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Axis] Disposal Group Name Disposal Groups Including Discontinued Operations Name [Domain] Philadelphia Marine Center (Marine Piers). Philadelphia Marine Center (Marine Piers) [Member] Philadelphia Marine Center Marine Piers [Member] Basis Of Presentation [Line Items] Basis Of Presentation [Line Items] Number of acquisitions for which adjustments have been made to correct errors related to of purchase price allocation Number Of Acquisitions For Which Adjustments Have Been Made To Correct Errors Related To Purchase Price Allocation Accounting Changes And Error Corrections [Abstract] Schedule Of Error Corrections And Prior Period Adjustment Restatement [Table] Schedule Of Error Corrections And Prior Period Adjustment Restatement [Table] Restatement Restatement [Axis] Restatement Restatement [Domain] As Previously Reported [Member] Scenario Previously Reported [Member] Adjustments [Member] Restatement Adjustment [Member] Error Corrections And Prior Period Adjustments Restatement [Line Items] Error Corrections And Prior Period Adjustments Restatement [Line Items] Operating properties Operating real estate investments, net Total assets General Partnership Capital Additional Paid-in Capital Cumulative Earnings Total Brandywine Operating Partnership, L.P.'s equity Total Brandywine Realty Trust's equity Noncontrolling interests Total beneficiaries' equity Total partners' equity Total liabilities and beneficiaries' equity Statement of Beneficiaries' Equity Net income attributable to Brandywine Realty Trust Direct financing leases Net Investment In Direct Financing And Sales Type Leases Operating leases expiration dates extending Lessor Operating Lease Option To Extend Leases [Abstract] 2019 (six months remaining) Lessor Operating Lease Payments To Be Received Remainder Of Fiscal Year 2019 Lessor Operating Lease Payments To Be Received Next Twelve Months 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 Lessor Operating Lease Payments To Be Received 2019 (six months remaining) Operating Leases Future Minimum Payments Receivable Remainder Of Fiscal Year 2019 Operating Leases Future Minimum Payments Receivable Current 2020 Operating Leases Future Minimum Payments Receivable In Two Years 2021 Operating Leases Future Minimum Payments Receivable In Three Years 2022 Operating Leases Future Minimum Payments Receivable In Four Years 2023 Operating Leases Future Minimum Payments Receivable In Five Years Thereafter Operating Leases Future Minimum Payments Receivable Thereafter Total Operating Leases Future Minimum Payments Receivable Lease Revenue Operating Leases Lease Income [Abstract] Fixed contractual payments Operating Lease Lease Income Lease Payments Variable lease payments Operating Lease Variable Lease Income Total Operating Lease Lease Income Number of grounds leasing under operating leases. Number of long-term ground leases Number Of Grounds Leasing Under Operating Leases Right of use asset - operating leases Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Property Operating Expenses [Member] Operating Expense [Member] Lease Cost Lease Cost [Abstract] Fixed lease cost Operating Lease Cost Variable lease cost Variable Lease Cost Total Lease Cost Weighted-average remaining lease term (years) Operating Lease Weighted Average Remaining Lease Term1 Weighted-average discount rate Operating Lease Weighted Average Discount Rate Percent Date of second installment payment. Rentable Square Feet Net Rentable Area Sales Price Disposal Group Including Discontinued Operation Consideration Payment by cash on purchases Payments To Acquire Businesses Net Of Cash Acquired Balance payment on purchase price Gain Contingency Unrecorded Amount Date of second installment payment Date Of Second Installment Payment Real estate investment including asset held for sale property at cost gross. Schedule Of Property Plant And Equipment [Table] Schedule Of Property Plant And Equipment [Table] Building and Improvements [Member] Building And Building Improvements [Member] Property Plant And Equipment [Line Items] Property Plant And Equipment [Line Items] Property, Plant and Equipment, Gross [Abstract] Real Estate Investment Property At Cost [Abstract] Land Land Tenant improvements Tenant Improvements Total Real Estate Investment Including Asset Held For Sale Property At Cost Gross Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Table] Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Table] Land [Member] Land [Member] Nine presidential boulevard. 9 Presidential Boulevard [Member] Nine Presidential Boulevard [Member] Libertyview [Member] Libertyview [Member] Libertyview [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] Acreage of Land Area Of Land Gain on Sale Contingent consideration to be received. Number of installments. Contingent consideration to received Contingent Consideration To Be Received Number of installments Number Of Installments Proceeds from the sale of properties Segments Statement Business Segments [Axis] Segments Segment [Domain] Other [Member] All Other Segments [Member] Investment Type Investment Type [Axis] Investments Investment Type Categorization [Member] Land held for development. Land Held For Development [Member] Land Held For Development [Member] Number of unconsolidated investments in Real Estate Ventures. Schedule Of Equity Method Investments [Table] Schedule Of Equity Method Investments [Table] Investment, Name Schedule Of Equity Method Investment Equity Method Investee Name [Axis] Investment, Name Equity Method Investee Name [Domain] Unconsolidated real estate ventures member. Unconsolidated Real Estate Ventures [Member] Unconsolidated Real Estate Ventures [Member] Investment Secondary Categorization Investment Secondary Categorization [Axis] Investments by Secondary Categorization Investments By Secondary Categorization [Domain] Six real estate ventures. Six Real Estate Ventures [Member] Six Real Estate Ventures [Member] Two real estate ventures. Two Real Estate Ventures [Member] Two Real Estate Ventures [Member] One real estate ventures. One Real Estate Venture [Member] One Real Estate Venture [Member] One other real estate ventures. One Other Real Estate Venture [Member] One Other Real Estate Ventures [Member] Land under active development. Land Under Active Development [Member] Land Under Active Development [Member] Residential tower. Residential Tower [Member] Residential Tower [Member] Statistical Measurement Range [Axis] Statistical Measurement Range [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Real estate venture. Real Estate Venture [Member] Real Estate Venture [Member] Management fees. Management Fees [Member] Management Fees [Member] Lease commission income. Leasing Commission Income [Member] Lease Commission Income [Member] MAP venture. MAP Venture [Member] M A P Venture [Member] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] Right of use asset. Right of Use Asset [Member] Right Of Use Asset [Member] Herndon innovation center metro portfolio venture, LLC. Herndon Innovation Center Metro Portfolio Venture, LLC [Member] Herndon Innovation Center Metro Portfolio Venture L L C [Member] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Secured Debt [Member] Secured Debt [Member] Distributions from loan one. Distributions from Loan 1 [Member] Distributions From Loan One [Member] Distributions from loan two. Distributions from Loan 2 [Member] Distributions From Loan Two [Member] PJP VII. PJP VII [Member] P J P V I I [Member] 4040 Wilson Venture [Member] 4040 Wilson Venture [Member] A4040 Wilson Venture [Member] Schedule Of Equity Method Investments [Line Items] Schedule Of Equity Method Investments [Line Items] Number of unconsolidated investments in Real Estate Ventures Number Of Unconsolidated Investments In Real Estate Ventures Investment in Real Estate Ventures, equity method Equity Method Investments Number of Property units Number Of Units In Real Estate Property Ownership percentage Equity Method Investment Ownership Percentage Service and other revenue Accounts receivable Equity Method Investment Summarized Financial Information Net Property. Equity Method Investment Summarized Financial Information Other Assets. Equity Method Investment Summarized Financial Information Other Liabilities. Equity method investment summarized financial information debt net. Net property Equity Method Investment Summarized Financial Information Net Property Other assets Equity Method Investment Summarized Financial Information Other Assets Other liabilities Equity Method Investment Summarized Financial Information Other Liabilities Debt, net Equity Method Investment Summarized Financial Information Debt Net Equity Equity Method Investment Summarized Financial Information Equity Or Capital evo at Cira Centre South Venture. evo at Cira Centre South [Member] Evo At Cira Centre South Venture [Member] Other. Other [Member] Other [Member] Revenue Equity Method Investment Summarized Financial Information Revenue Operating expenses Equity Method Investment Summarized Financial Information Operating Expenses Interest expense, net Equity Method Investment Summarized Financial Information Interest Expense Net Depreciation and amortization Equity Method Investment Summarized Financial Information Depreciation And Amortization Loss on early extinguishment of debt Equity Method Investment Summarized Financial Information Loss On Extinguishment Of Debt Net income (loss) Equity Method Investment Summarized Financial Information Net Income Loss Ownership interest % Company's share of net income (loss) Equity Method Investment Summarized Financial Information Net Income Loss Before Adjustments Basis adjustments and other Equity Method Investment Summarized Financial Information On Basis Adjustments And Other Equity in income (loss) of Real Estate Ventures Lessee under ground lease term. Number of lessee properties and unit to property. Number of lessee land parcels Number Of Lessee Properties And Unit To Property Lessee under ground lease term Lessee Under Ground Lease Term Indebtedness to third parties, refinanced amount Debt Instrument Face Amount Debt instrument, initial advance Proceeds From Issuance Of Debt Debt instrument, basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Effective interest rate Debt Instrument Interest Rate Effective Percentage Debt instrument maturity date Debt Instrument Maturity Date Debt Instrument, interest rate, stated percentage Debt Instrument Interest Rate Stated Percentage Debt Instrument, maturity date Debt Instrument Maturity Date Range Start1 Equity method investment summarized financial information debt. Real estate ventures aggregate indebtedness Equity Method Investment Summarized Financial Information Debt Guarantees, maximum exposure amount Guarantee Obligations Maximum Exposure Construction loan, principal amount Construction Loan Construction loan total borrowing capacity Debt Instrument Unused Borrowing Capacity Amount Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table] Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table] Finite-Lived Intangible Assets by Major Class Finite Lived Intangible Assets By Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name Finite Lived Intangible Assets Major Class Name [Domain] In-place lease value [Member] Leases Acquired In Place [Member] Tenant relationship value [Member] Customer Relationships [Member] Above market leases acquired [Member] Above Market Leases [Member] Below market leases. Below Market Lease Below Market Lease [Axis] Below market leases. Below Market Lease Below Market Lease [Domain] Below market leases acquired including liabilities of assets held for sale. Below market leases [Member] Below Market Leases Acquired Including Liabilities Of Assets Held For Sale [Member] Intangible Assets [Line Items] Acquired Finite Lived Intangible Assets [Line Items] Intangible Assets, Total Cost Finite Lived Intangible Assets Gross Intangible Assets, Accumulated Amortization Finite Lived Intangible Assets Accumulated Amortization Intangible Assets, net Acquired Lease Intangibles, Gross Below Market Lease Gross Acquired Lease Intangibles, Accumulated Amortization Below Market Lease Accumulated Amortization Acquired Lease Intangibles, Net Assets Finite Lived Intangible Assets Future Amortization Expense [Abstract] 2019 (six months remaining) Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year 2020 Finite Lived Intangible Assets Amortization Expense Year Two 2021 Finite Lived Intangible Assets Amortization Expense Year Three 2022 Finite Lived Intangible Assets Amortization Expense Year Four 2023 Finite Lived Intangible Assets Amortization Expense Year Five Thereafter Finite Lived Intangible Assets Amortization Expense After Year Five Liabilities Below Market Lease Net Amortization Income Fiscal Year Maturity [Abstract] 2019 (six months remaining) Below Market Lease Amortization Income Remainder Of Fiscal Year 2020 Below Market Lease Amortization Income Year Two 2021 Below Market Lease Amortization Income Year Three 2022 Below Market Lease Amortization Income Year Four 2023 Below Market Lease Amortization Income Year Five Thereafter Below Market Lease Amortization Income After Year Five Consolidated Debt Obligations Abstract. Secured debt net of premiums discount. Debt Instrument [Table] Debt Instrument [Table] Unsecured Debt [Member] Unsecured Debt [Member] Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Unsecured credit facility. $600 million Unsecured Credit Facility [Member] Unsecured Credit Facility [Member] Seven year term loan. Seven Year Term Loan - Swapped to fixed [Member] Seven Year Term Loan [Member] $250.0M 3.950% Guaranteed Notes due 2023 $350M 3.95% Guaranteed Notes due 2023 [Member] Note2023 [Member] Note 2024 [Member] $250.0M 4.10% Guaranteed Notes due 2024 [Member] Note2024 [Member] Note 2027. $450.0M 3.95% Guaranteed Notes due 2027 [Member] Note2027 [Member] Note 2029 [Member] $250M 4.55% Guaranteed Notes due 2029 [Member] Note2029 [Member] Indenture IA (Preferred Trust I). Indenture IA (Preferred Trust I) [Member] Indenture Ia Preferred Trust I [Member] Indenture IB (Preferred Trust I). Indenture IB (Preferred Trust I) - Swapped to fixed [Member] Indenture Ib Preferred Trust I [Member] Indenture II (Preferred Trust II). Indenture II (Preferred Trust II) - Swapped to fixed [Member] Indenture Ii Preferred Trust Ii [Member] Property location. Property Location Property Location [Axis] Property location. Property Location Property Location [Domain] Two Logan Square. Two Logan Square [Member] Two Logan Square [Member] Four tower bridge. Four Tower Bridge [Member] Four Tower Bridge [Member] One Commerce Square at 2005 Market St, Philadelphia PA One Commerce Square [Member] One Commerce Square [Member] Two Commerce Square at 2001 Market St, Philadelphia PA Two Commerce Square [Member] Two Commerce Square [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Consolidated debt obligations Consolidated Debt Obligations [Abstract] Long-term Debt, Gross Debt Instrument Carrying Amount Plus: premiums/(discounts), net Debt Instrument Unamortized Discount Premium Net Less: deferred financing costs Deferred Finance Costs Net Total mortgage indebtedness Secured Debt Net Of Premiums Discount Total unsecured indebtedness Unsecured Indebtedness Total Debt Obligations Long Term Debt Effective interest rate Debt instrument, description of variable rate basis Debt Instrument Description Of Variable Rate Basis Spread on variable rate Unsecured credit facility, maximum borrowing capacity Line Of Credit Facility Maximum Borrowing Capacity Debt instrument maturity year. Debt instrument interest rate Debt instrument maturity year Debt Instrument Maturity Year Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] LIBOR [Member] London Interbank Offered Rate L I B O R [Member] New Credit Facility [Member] New Credit Facility [Member] New Credit Facility [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Long-term Debt, Weighted Average Interest Rate Longterm Debt Weighted Average Interest Rate Maximum borrowing capacity Line of Credit Interest expense, borrowings Interest Expense Borrowings Effective interest rate on credit facility Line Of Credit Facility Interest Rate At Period End 2019 (six months remaining) Long Term Debt Maturities Repayments Of Principal Remainder Of Fiscal Year 2020 Long Term Debt Maturities Repayments Of Principal In Year Two 2021 Long Term Debt Maturities Repayments Of Principal In Year Three 2022 Long Term Debt Maturities Repayments Of Principal In Year Four 2023 Long Term Debt Maturities Repayments Of Principal In Year Five Thereafter Long Term Debt Maturities Repayments Of Principal After Year Five Total principal payments Long Term Debt Maturities Repayments Of Principal Net unamortized premiums/(discounts) Net deferred financing costs Fair Value By Balance Sheet Grouping [Table] Fair Value By Balance Sheet Grouping [Table] Measurement Basis Fair Value By Measurement Basis [Axis] Fair Value Disclosure Item Amounts [Default] Portion At Fair Value Fair Value Disclosure [Member] Fair Value Measurement Fair Value Disclosure Item Amounts [Domain] Carrying Amount [Member] Carrying Reported Amount Fair Value Disclosure [Member] Unsecured Notes Payable [Member] Variable rate debt. Variable Rate Debt [Member] Variable Rate Debt [Member] Mortgages Notes Payable [Member] Mortgages [Member] Fair Value [Member] Estimate Of Fair Value Fair Value Disclosure [Member] Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] Unsecured notes payable Notes Payable Variable rate debt Loans Payable Notes receivable Loans And Leases Receivable Before Fees Gross Debt instrument, fair value Debt Instrument Fair Value Note receivable, fair value Loans Receivable Fair Value Disclosure Deferred financing costs, net Brandywine 1919 Ventures. Brandywine 1919 Ventures [Member] Brandywine Nineteen Nineteen Ventures [Member] Brandywine 1919 Ventures [Member] Balance Sheet Location Balance Sheet Location [Axis] Balance Sheet Location Balance Sheet Location [Domain] Other Assets [Member] Other Assets [Member] Mortgage loan Mortgage Loans On Real Estate Equity method investment, ownership percentage Note receivable Notes Receivable Gross Minority interest in operating partnerships settlement value. Aggregate amount related to non-controlling interests classified within equity Minority Interest In Operating Partnerships Settlement value of non controlling interest in operating partnership Minority Interest In Operating Partnerships Settlement Value Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Derivative Instrument Derivative Instrument Risk [Axis] Derivative Contract Derivative Contract Type [Domain] 3.090% Interest Rate Swap Maturing October 30, 2019 [Member] 3.090% Interest Rate Swap Maturing October 30, 2019 [Member] A3090 Interest Rate Swap Maturing October302019 [Member] 2.868 Interest Rate Swap Maturing October 8, 2022 [Member] 2.868% Interest Rate Swap Maturing October 8, 2022 [Member] A2868 Interest Rate Swap Maturing October82022 [Member] 3.300% Interest Rate Swap Maturing January 30, 2021 [Member] 3.300% Interest Rate Swap Maturing January 30, 2021 [Member] A3300 Interest Rate Swap Maturing January302021 [Member] Hedging Relationship Derivative Instruments Gain Loss By Hedging Relationship [Axis] Hedging Relationship Hedging Relationship [Domain] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Derivatives Fair Value [Line Items] Derivatives Fair Value [Line Items] Notional Amount Derivative Notional Amount Derivative Asset, Notional Amount Derivative Asset Notional Amount Derivative Liability, Notional Amount Derivative Liability Notional Amount Derivative, Fixed Interest Rate Derivative Fixed Interest Rate Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement Derivative Asset Fair Value Gross Asset Including Not Subject To Master Netting Arrangement Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Derivative Liability Fair Value Gross Liability Including Not Subject To Master Netting Arrangement Incremental common shares attributable to share based payment arrangements basic. Numerator Earnings Per Share Reconciliation [Abstract] Net income Net income attributable to noncontrolling interests, Basic Nonforfeitable dividends allocated to unvested restricted shareholders, Basic Denominator Weighted Average Number Of Shares Outstanding [Abstract] Basic weighted average shares outstanding (in shares) Basic contingent securities/Share based compensation (in shares) Incremental Common Shares Attributable To Share Based Payment Arrangements Basic Earnings per Common Share: Earnings Per Share [Abstract] Net income attributable to common shareholders, Basic (USD per share) Earnings Per Share Basic Net income attributable to noncontrolling interests, Diluted Net Income Loss Attributable To Noncontrolling Interest Diluted Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted Undistributed Earnings Loss Allocated To Participating Securities Diluted Net income attributable to common shareholders, Diluted Net Income Loss Available To Common Stockholders Diluted Contingent securities/Share based compensation (in shares) Incremental Common Shares Attributable To Share Based Payment Arrangements Diluted weighted average shares outstanding (in shares) Net income attributable to common shareholders, Diluted (USD per share) Earnings Per Share Diluted Schedule Of Stock By Class [Table] Schedule Of Stock By Class [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Redeemable common limited partnership units. Redeemable Common Limited Partnership Units [Member] Redeemable Common Limited Partnership Units [Member] Dividends Dividends [Axis] Dividends Dividends [Domain] Dividend Declared [Member] Dividend Declared [Member] Class of Stock [Line Items] Class Of Stock [Line Items] Redeemable Common Limited Partnership Units Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Dividends Payable, Amount Per Share Dividends Payable Amount Per Share Dividends, Common Stock Dividends Common Stock Dividends payable, date to be paid Dividend Payable Date To Be Paid Day Month And Year Dividends payable, date of record Dividends Payable Date Of Record Day Month And Year Authorized Amount Stock Repurchase Program Authorized Amount1 Repurchased and Retired, Shares Share Price Treasury Stock Acquired Average Cost Per Share Repurchased and Retired, Value Net Income (Loss) available to common unitholders, basic Net Income (Loss) Available to Common Unit holders, Diluted. Net income attributable to noncontrolling interests Noncontrolling Interest In Net Income Loss Joint Venture Partners Redeemable Net income attributable to common unitholders, Basic Net Income Loss Available To Common Unitholders Basic Denominator Weighted Average Number Of Shares Outstanding Diluted Disclosure Items [Abstract] Earnings per Common Partnership Unit: Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted Net income attributable to common unitholders, Diluted Net Income Loss Available To Common Unit Holders Diluted Repurchase program number of mirror unit of operating partnership retired for each common share repurchased. Stock retired during period, shares. Stock retired during period, value. Earnings per common partnership unit line items. Earnings per Common Partnership Unit. Earnings Per Common Partnership Unit [Table] Earnings Per Common Partnership Unit [Table] Earnings Per Common Partnership Unit [Line Items] Earnings Per Common Partnership Unit [Line Items] Repurchase program, number of mirror unit of operating partnership retired for each common share repurchased Repurchase Program Number Of Mirror Unit Of Operating Partnership Retired For Each Common Share Repurchased Number of shares, retired Stock Retired During Period Shares Number of shares, retired Share Price Stock retired, value Stock Retired During Period Value Repurchased and Retired, Value Number of Reportable Segments Number Of Reportable Segments Operating real estate investment property held for use at cost. Schedule Of Segment Reporting Information By Segment [Table] Schedule Of Segment Reporting Information By Segment [Table] Philadelphia CBD. Philadelphia CBD [Member] Philadelphia C B D [Member] Pennsylvania suburbs. Pennsylvania Suburbs [Member] Pennsylvania Suburbs [Member] Austin Texas. Austin, Texas [Member] Austin Texas [Member] Metropolitan, D.C. Metropolitan DC [Member] Metropolitan D C [Member] Other [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Operating properties Operating Real Estate Investment Property Held For Use At Cost Business Acquisition Business Acquisition [Axis] Business Acquisition, Acquiree Business Acquisition Acquiree [Domain] 3001-3003 and 3025 JFK Boulevard. 3001-3003 and 3025 JFK Boulevard [Member] Three Thousand One And Three Thousand Three And Three Thousand Twenty Five J F K Boulevard [Member] Consolidation Items Consolidation Items [Axis] Consolidation Items Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Corporate [Member] Corporate Non Segment [Member] Total revenue Operating expenses Cost Of Goods And Services Sold Net operating income (loss) Gross Profit DRA Austin Venture. DRA Austin Venture [Member] D R A Austin Venture [Member] Herndon Innovation Center Metro Portfolio Venture, LLC [Member] Metropolitan D.C. - Office. Metropolitan Washington, D.C. - Office [Member] Metropolitan D C Office [Member] Legal Entity Legal Entity [Axis] Entity Entity [Domain] Rockpoint. Rockpoint [Member] Rockpoint [Member] Area of Real Estate Property Number of properties contributed to joint venture. Number of properties contributed to a joint venture Number Of Properties Contributed To Joint Venture Investment in real estate ventures Equity in income (loss) of real estate venture Plus: Other Income Disclosure Nonoperating [Abstract] Interest expense Interest expense - amortization of deferred financing costs Equity in loss of Real Estate Ventures Less: Other Expense Disclosure Nonoperating [Abstract] Net gain on real estate venture transactions Consolidated net operating income Property Subject To Or Available For Operating Lease By Major Property Class [Table] Property Subject To Or Available For Operating Lease By Major Property Class [Table] Mortgage Lenders [Member] Minimum [Member] Maximum [Member] 618 Market Street [Member] 618 Market Street [Member] A618 Market Street [Member] The Bulletin Building. The Bulletin Building [Member] The Bulletin Building [Member] Drexel Square. Drexel Square [Member] Drexel Square [Member] Property Subject to or Available for Operating Lease [Line Items] Property Subject To Or Available For Operating Lease [Line Items] Associated letter of credit Letters Of Credit Outstanding Amount Lease terms Lessee Operating Lease Term Of Contract Adoption of Topic 842 [Member] Accounting Standards Update201602 [Member] 2019 (six months remaining) 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 operating lease liabilities 2019 Operating Leases Future Minimum Payments Due Current 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 Contingent consideration, liability Business Combination Contingent Consideration Liability Fair value of contingent consideration Business Combination Step Acquisition Equity Interest In Acquiree Fair Value1 Interest expense Interest Expense Real estate ventures aggregate indebtedness Loan outstanding principal balance General allowance for remaining portfolio of operating leases considered collectible Loans And Leases Receivable Allowance Excess estimated ground lease funding. Estimated redevelopment costs. Required spending in capital improvements to property Contractual Obligation Funding requirement met for capital improvements Payments For Capital Improvements Expected excess redevelopment funding Excess Estimated Ground Lease Funding Estimated aggregate cost Estimated Redevelopment Costs Acquisition cost, inclusive in estimated aggregate cost Business Combination Separately Recognized Transactions Additional Disclosures Acquisition Costs Estimated potential additional contribution obligation. Estimated potential additional contribution obligation Estimated Potential Additional Contribution Obligation