Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Denominator Weighted Average Number of Shares Outstanding, Diluted [Abstract] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Statistical Measurement [Domain] Statistical Measurement [Domain] Title of 12(b) Security Title of 12(b) Security Net loss attributable to common unitholders, diluted Net Income (Loss) Available to Common Stockholders, Diluted Carrying Amount Reported Value Measurement [Member] Document Fiscal Year Focus Document Fiscal Year Focus Weighted-average interest rate Debt, Weighted Average Interest Rate Repurchase and retirement of LP units Partners Capital Account Repurchased And Retired Partners capital account repurchased and retired. Total partners' equity Beginning balance Ending balance Partners' Capital, Including Portion Attributable to Noncontrolling Interest Adjustment to Compensation, Amount Adjustment to Compensation Amount Derivative liability, fair value, gross liability Interest Rate Fair Value Hedge Liability at Fair Value Real Estate [Line Items] Real Estate [Line Items] Accrued rent receivable, net of allowance of $369 and $424 as of September 30, 2026 and December 31, 2025, respectively Accrued rent receivable, net of allowance of $369 and $424 as of September 30, 2026 and December 31, 2025, respectively Deferred Rent Receivables, Net Segment Reporting [Abstract] Segment Reporting [Abstract] Advances for the purchase of tenant assets, net of repayments Advances for the purchase of tenant assets, net of repayments Advances To Tenant For Purchase Of Tenant Assets, Net Of Repayments Advances for purchase of tenant assets, net of repayments. Austin, Texas Austin, Texas Austin, Texas [Member] Austin Texas. Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 400,000,000; 170,026,338 and 173,699,039 issued and outstanding as of September 30, 2026 and December 31, 2025, respectively Common Stock, Value, Issued 2026 (three months remaining) Below Market Lease, Amortization Income, Remainder of Fiscal Year Restatement Determination Date Restatement Determination Date Derivative Instrument [Axis] Derivative Instrument [Axis] $350.0M 7.55% Guaranteed Notes due 2028 8.30% Note 2028 [Member] Note 2028 Real Estate Venture Real Estate Venture [Member] Real estate venture. In-place lease value Leases, Acquired-in-Place [Member] Gain (loss) on disposition of property plant equipment offset by debt extinguishment Gain (Loss) on Disposition of Property Plant Equipment Offset by Debt Extinguishment Gain (Loss) on Disposition of Property Plant Equipment Offset by Debt Extinguishment Amendment Flag Amendment Flag Consolidated Entities Consolidated Entities [Axis] Class A Units Class Units [Member] Class A Units [Member] Share price (in dollars per share) Shares Acquired, Average Cost Per Share Proceeds from secured term loan Proceeds from Secured Notes Payable Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Accumulated depreciation Accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Disposal Group Classification [Axis] Disposal Group Classification [Axis] Third party management expenses Third party management expenses Third Party Management Expenses Third party management expenses. Schedule 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 [Table Text Block] Schedule of core portfolio of operating properties and excludes development and redevelopment properties under construction. Property operating expenses Property operating expenses Cost of Other Property Operating Expense Loss Contingencies [Table] Loss Contingencies [Table] Cumulative distributions Cumulative Dividends Repurchase program, ratio of mirror unit of operating partnership retired for each common share repurchased (in shares) 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. Leases [Abstract] Leases [Abstract] Comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Intangible Assets [Line Items] Intangible Asset, Finite-Lived, Acquired [Line Items] Payment guaranty percentage Long-Term Debt, Payment Guaranty, Percentage of Principle Balance Long-Term Debt, Payment Guaranty, Percentage of Principle Balance Consolidated Entities Consolidated Entities [Domain] Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Entity Address, State or Province Entity Address, State or Province PEO Total Compensation Amount PEO Total Compensation Amount Common stock, par or stated value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Notional Amount Derivative, Notional Amount Basic weighted average shares outstanding (in shares) Basic weighted average common partnership units outstanding (in shares) Total weighted-average units outstanding, basic (in shares) Weighted Average Number of Shares Outstanding, Basic Secured term loans, net Fixed rate debt Secured Debt Schedule of Amortization for Intangible Assets and Liabilities Finite Lived Intangible Assets And Liabilities Amortization Expense Table [Table Text Block] Finite lived intangible assets and liabilities amortization expense table text block. Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Construction Loans Construction Loans [Member] Number of reportable segments Number of Reportable Segments Tenant relationship value Customer Relationships [Member] Tender Offer and Open-market Purchase Tender Offer and Open-market Purchase [Member] Tender Offer and Open-market Purchase Service and other revenue Revenue from Contract with Customer, Including Assessed Tax Entity Address, City or Town Entity Address, City or Town Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Document Information [Line Items] Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] Class of Stock [Axis] Intangible Assets, net Intangible Asset, Finite-Lived, after Accumulated Amortization Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount 2028 Notes and 8.88% Notes Due 2029 2028 Notes and 8.88% Notes Due 2029 [Member] 2028 Notes and 8.88% Notes Due 2029 Capital distributions from unconsolidated real estate ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Net loss attributable to Common Shareholders of Brandywine Realty Trust Net loss attributable to Common Partnership Unitholders of Brandywine Operating Partnership, L.P. Net Income (Loss) Available to Common Stockholders, Basic Intangible liabilities, net: Below Market Lease [Abstract] Accumulated Amortization Intangible Asset, Finite-Lived, Accumulated Amortization Other income (expense): Other income (expense): Nonoperating Income (Expense) [Abstract] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Maximum borrowing capacity (up to) Line of Credit Facility, Maximum Borrowing Capacity Total comprehensive income (loss) Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Ground rent expense Ground rent expense Straight Line Ground Rent Expense Straight line ground rent expense. Parent Company Parent Company [Member] Name of Property [Axis] Name of Property [Axis] Schedule of Long-Term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] 2030 Below Market Lease, Amortization Income, Year Four Deferred income, gains and rent Deferred income, gains and rent Increase (Decrease) in Contract with Customer, Liability Gain on property disposition Gain (Loss) on Disposition of Property Plant Equipment Schedule of Real Estate Investments, Net Operating Income and Unconsolidated Real Estate Ventures of Reportable Segments Segment Reporting [Table Text Block] Noncontrolling Interests Noncontrolling Interest - Consolidated Real Estate Ventures Noncontrolling Interest [Member] 2029 Below Market Lease, Amortization Income, Year Three Use of Estimates Use of Estimates, Policy [Policy Text Block] Interest expense - amortization of deferred financing costs Amortization of deferred financing costs Interest expense - amortization of deferred financing costs Interest expense - amortization of deferred financing costs Amortization of Debt Issuance Costs Unsecured term loans, net Unsecured notes payable Unsecured Debt [Member] Limited Partners' Noncontrolling Interests in the Parent Company Noncontrolling Interest Disclosure [Text Block] Net loss attributable to noncontrolling interests Net Income (Loss) Attributable To Noncontrolling Interest Diluted Net income loss attributable to noncontrolling interest diluted. Schedule of Financial Position of Real Estate Ventures Summary Investment Holdings [Table Text Block] Debt, net Outstanding indebtedness Long-Term Debt Supplemental disclosure of non-cash activity: Supplemental disclosure of non-cash activity: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Document Period End Date Document Period End Date Changes in assets and liabilities: Changes in assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] General Partnership Capital; 170,026,338 and 173,699,039 units issued and outstanding as of September 30, 2026 and December 31, 2025, respectively General Partners' Capital Account Net cash provided by (used in) investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Debt instrument, face amount Debt Instrument, Face Amount Total gain on sale of real estate Gain (Loss) on Sale of Properties Redeemable limited partnership units outstanding (in shares) Temporary Equity, Shares Outstanding Operating expenses Operating expenses Costs and Expenses [Abstract] Security Exchange Name Security Exchange Name $300.0M 6.13% Guaranteed Notes due 2031 6.13% Notes Due 2031 [Member] 6.13% Notes Due 2031 Unconsolidated real estate venture debt at 100%, gross Equity Method Investment Summarized Financial Information Debt Equity method investment summarized financial information debt. Effective Interest Rate Effective interest rate Debt Instrument, Interest Rate, Effective Percentage One Uptown Multi-Family Venture One Uptown Venture One Uptown Venture [Member] One Uptown Venture Extinguishment of Debt, Type [Domain] Extinguishment of Debt, Type [Domain] Equity Method Investment, Nonconsolidated Investee [Axis] Equity Method Investment, Nonconsolidated Investee [Axis] Leases Lessor, Operating Leases [Text Block] 3025 JFK Construction Loan 3025 JFK Construction Loan [Member] 3025 JFK Construction Loan Area of land (in acres) Area of Land Other-than-temporary impairment Equity Method Investment, Other-than-Temporary Impairment Accumulated other comprehensive income (loss) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items Consolidation Items [Domain] Wholly-owned Management Company Subsidiaries Management Company Subsidiaries [Member] Management company subsidiaries. Principal balance outstanding Mortgages [Member] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Schedule of Gross Carrying Value of Operating Properties Schedule of Real Estate Properties [Table Text Block] Name Outstanding Recovery, Individual Name Loss per Common Share: Loss per Common Partnership Unit: Earnings Per Share [Abstract] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Earnings Per Common Partnership Unit [Line Items] Earnings Per Common Partnership Unit [Line Items] Earnings per common partnership unit line items. Total liabilities Liabilities Trading Symbol Trading Symbol Interest expense borrowings Interest Expense, Borrowings General Partner Capital Partner Type [Axis] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Term Loan - Swapped to fixed Term Loan [Member] term loan. Company Selected Measure Name Company Selected Measure Name Distributions to noncontrolling interest Payments of Ordinary Dividends, Noncontrolling Interest Operating real estate investments, net Operating Real Estate Investment Property Net Operating real estate investment property net. Thereafter Below Market Lease, Amortization Income, After Year Four Below Market Lease, Amortization Income, After Year Four Strike Derivative, Fixed Interest Rate Mid-Atlantic Office JV Mid-Atlantic Office JV Loan [Member] Mid-Atlantic Office JV Loan Ownership in the operating partnership Subsidiary, Ownership Percentage, Parent Principal balance outstanding Total principal payments Long-Term Debt, Gross Depreciation and amortization Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Cash flows from operating activities: Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] MAP Venture M A P Venture [Member] MAP venture. Beginning balance (in shares) Ending balance (in shares) Shares, Issued Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Diluted weighted average shares outstanding (in shares) Diluted weighted average common partnership units outstanding (in shares) Total weighted-average units outstanding, diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Leasing Commission Income Lease Commission Income [Member] Lease commission income. Investment in unconsolidated real estate ventures Investment in unconsolidated real estate ventures Equity Method Investments In Asset Position Equity Method Investments In Asset Position Entity Emerging Growth Company Entity Emerging Growth Company Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Leasing costs paid Leasing costs paid Payment for Initial Direct Cost, Lease, Investing Activity Disposal Group Name [Domain] Disposal Group Name [Domain] Underlying Security Market Price Change Underlying Security Market Price Change, Percent 2028 Below Market Lease, Amortization Income, Year Two Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Distributions payable Dividends and distributions declared but not paid Dividends Payable Interest Rate Swap, 3.713% 3.713% Interest Rate Swap Maturing June 30, 2027 [Member] 3.713% Interest Rate Swap Maturing June 30, 2027 Pennsylvania Suburbs Pennsylvania Suburbs Pennsylvania Suburbs [Member] Pennsylvania suburbs. Prepaid leasehold interests in land held for development, net Prepaid leasehold interests in land held for development, net Prepaid Expense Net operating income Consolidated net operating income Gross Profit Continuing Operations Continuing Operations [Member] Straight-line rent income Straight-line rent income Straight Line Rent Excluding Rent Termination Fee Straight-line rent excluding rent termination fee. Share Issuance from/(to) Deferred Compensation Plan (in shares) Deferred compensation obligation (in shares) Share Issuance From (To) Deferred Compensation Plan Shares Share issuance from/to deferred compensation plan shares. Reallocation of Noncontrolling interest Noncontrolling Interest Increase Decrease From Reallocation Noncontrolling interest increase decrease from reallocation. Award Timing Predetermined Award Timing Predetermined [Flag] Intangible Asset, Goodwill and Other [Abstract] Intangible Asset, Goodwill and Other [Abstract] Repayments of unsecured term loan Repayment of unsecured term loan Repayments of Unsecured Debt Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Settlement value of non controlling interest in operating partnership Minority Interest In Operating Partnerships Settlement Value Minority interest in operating partnerships settlement value. Preferred Equity Investment Obligation Preferred Equity Investment Obligation [Member] Preferred Equity Investment Obligation [Member] Parcel of land Land Parcel One [Member] Land parcel one. Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Derivative asset, notional amount Derivative Asset, Notional Amount Area of real estate property (in square feet) Rentable Square Feet (in square feet) Area of Real Estate Property Distributions paid to shareholders Distributions paid to preferred and common partnership units Payment Of Ordinary Dividends, Common Stock And Preferred Stock Payment Of Ordinary Dividends, Common Stock And Preferred Stock Organization Of Parent Company And Operating Partnership [Table] Organization Of Parent Company And Operating Partnership [Table] Organization of The Parent Company and The Operating Partnership. All Executive Categories All Executive Categories [Member] Repurchase and retirement of Common Shares of Beneficial Interest Value of stock repurchased and retired Stock Repurchased and Retired During Period, Value Investments Secondary Categorization Investments Secondary Categorization [Axis] Investments Secondary Categorization Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Organization of The Parent Company and The Operating Partnership [Line Items] Organization Of Parent Company And Operating Partnership [Line Items] Organization of The Parent Company and The Operating Partnership. Repayments of credit facility borrowings Repayments of credit facility borrowings Repayments of Long-Term Lines of Credit Rabbi Trust/Deferred Compensation Shares Deferred Compensation, Share-Based Payments [Member] Other Real Estate, Other [Member] Repayments of construction loan Repayments of Construction Loans Payable Antidilutive Securities Antidilutive Securities [Axis] Partner Type of Partners' Capital Account, Name Partner Type of Partners' Capital Account, Name [Domain] Reconciliation of cash and cash equivalents and restricted cash: Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation [Abstract] Right of use asset - operating leases, net Right of use asset - operating leases, net Operating Lease, Right-of-Use Asset Management Fees Management Fees [Member] Management fees. Real estate investments: Real estate investments: Real Estate Investments, Net [Abstract] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Segment Information Segment Reporting [Text Block] Minimum Minimum [Member] Unsecured credit facility Long-Term Line of Credit Expiration Date Trading Arrangement Expiration Date 2030 Long-Term Debt, Maturity, Year Four Hedging Relationship Hedging Relationship [Axis] Real Estate [Table] Real Estate [Table] Denominator Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Restricted cash, beginning of period Restricted cash, end of period Restricted Cash and Cash Equivalent Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Total beneficiaries' equity Beginning balance Ending balance Equity Equity, Including Portion Attributable to Noncontrolling Interest Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Building Building [Member] Real Estate Property, Ownership [Table] Real Estate Property, Ownership [Table] Lease agreement term Lease Agreement Term Lease agreement term. Other liabilities Other liabilities Other Liabilities Dividends, common stock Amount of dividend declared Dividends, Common Stock Unsecured loans, net Unsecured Debt Extension term Debt Instrument, Extension Term Debt Instrument, Extension Term 2027 Below Market Lease, Amortization Income, Year One Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Daily Simple SOFR Daily Simple SOFR [Member] Daily Simple SOFR Common stock, shares authorized (in shares) Common Stock, Shares Authorized Numerator Numerator Earnings Per Share Reconciliation [Abstract] Total real estate investments, net Net property Real Estate Investment Property, Net Number of apartment Number of Units in Real Estate Property 7.55% Note 2028 7.55% Note 2028 [Member] 7.55% Note 2028 Plus: original issue premium (discount), net Net unamortized premiums/(discounts) Debt Instrument, Unamortized Discount (Premium), Net Exercise Price Award Exercise Price Cash flows from investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Segment Reporting [Line Items] Segment Reporting [Line Items] Authorized amount Share Repurchase Program, Authorized, Amount Document Quarterly Report Document Quarterly Report Common shares in grantor trust, 2,288,739 and 1,583,000 issued and outstanding as of September 30, 2026 and December 31, 2025, respectively Common Stock, Held-in-Trust Unconsolidated Real Estate Ventures Unconsolidated Real Estate Ventures [Member] Unconsolidated real estate ventures member. Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Segments [Domain] Segments [Domain] Accounts receivable Accounts receivable Accounts Receivable, after Allowance for Credit Loss Net loss attributable to noncontrolling interests Noncontrolling Interest in Net Income (Loss) Joint Venture Partners, Redeemable Debt Obligations Debt Disclosure [Text Block] Contractual obligation Contractual Obligation Operating Activities [Domain] Operating Activities [Domain] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Less: deferred financing costs Net deferred financing costs Deferred financing costs, net Debt Issuance Costs, Net Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Investment in unconsolidated real estate ventures Equity Method Investments Real Estate Investments Real Estate Disclosure [Text Block] Proceeds from unsecured term loan Proceeds from unsecured term loan Proceeds from unsecured term loan Equity Component Equity Component [Domain] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Fixed rate debt Secured Debt [Member] Real estate taxes Real estate taxes Real Estate Tax Expense Deferred costs, net Deferred costs, net Deferred Costs Daily SOFR Adjustment Daily SOFR Adjustment [Member] Daily SOFR Adjustment Real Estate Properties Real Estate Properties [Domain] Plus: Other Income, Nonoperating [Abstract] Total operating expenses Operating expenses Costs and Expenses Adoption Date Trading Arrangement Adoption Date Debt Covenant Period [Axis] Debt Covenant Period [Axis] Debt Covenant Period Dispositions Disposal Group, Including Discontinued Operation, Consideration Investment in unconsolidated real estate ventures Investment in unconsolidated real estate ventures Payments to Acquire Equity Method Investments Funding for Tenant and Capital Improvement of Properties Additional Funding For Tenant And Capital Improvement Of Properties [Member] Additional Funding For Tenant And Capital Improvement Of Properties Debt instrument, interest rate, stated percentage Debt Instrument, Interest Rate, Stated Percentage Distributions declared Dividends, Common Stock, Cash Total Brandywine Realty Trust's equity Equity, Attributable to Parent Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Real Estate [Domain] Real Estate [Domain] ASSETS Assets [Abstract] Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Total Core Segments Core Segment, Total [Member] Core Segment, Total Capital expenditures for redevelopments Capital expenditures for redevelopments Payments To Redevelop Real Estate Payments to redevelop real estate - Capital expenditures to redevelop real estate. Accounting Policies [Abstract] Accounting Policies [Abstract] Accrued rent receivable, allowance Allowance For Doubtful Accrued Rent Receivable Allowance for doubtful accrued rent receivable. Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Lease liability - operating leases Operating Lease, Liability Insider Trading Policies and Procedures [Line Items] Philadelphia CBD Philadelphia CBD Philadelphia C B D [Member] Philadelphia CBD. Gain on sale of real estate Gain on sale of real estate Gain Loss On Sale Of Properties [Abstract] Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Noncontrolling interest - consolidated real estate ventures Partners' Capital Attributable to Noncontrolling Interest Thereafter Long-Term Debt, Maturity, After Year Four Long-Term Debt, Maturity, After Year Four Business Combination Business Combination [Domain] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Total Operating Lease, Lease Income Less: Other Expense, Nonoperating [Abstract] Redeemable common limited partnership units (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Net gain on real estate venture transactions Net Gain (Loss) On Real Estate Venture Transactions Including Real Estate Venture Formation Net gain (loss) on real estate venture transactions including real estate venture formation. Entity Central Index Key Entity Central Index Key All Adjustments to Compensation All Adjustments to Compensation [Member] Name of Property [Domain] Name of Property [Domain] Corporate Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Business Combination Business Combination [Axis] Brandywine Realty Trust's Equity: Brandywine Operating Partnership, L.P.'s equity: Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Net cash provided by operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation 2026 (three months remaining) Long-Term Debt, Maturity, Remainder of Fiscal Year Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Areas of land held for development (in acres) Area Of Land Held For Development Area of land held for development. Ownership Ownership [Axis] Area of additional undeveloped parcels of land with option to purchase (in acres) Area Of Additional Undeveloped Parcels Of Land With Option To Purchase Area of additional undeveloped parcels of land with option to purchase. Investment, Name [Axis] Investment, Name [Axis] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Distributions to general partnership unitholders (in dollars per share) Distributions Per General Partnership Unit Outstanding Number of extensions Debt Instrument, Number Of Extensions Debt Instrument, Number Of Extensions Building and improvements Investment Building and Building Improvements Carry Guarantee Carry Guarantee [Member] Carry Guarantee Intangible Asset, Finite-Lived, Acquired [Table] Intangible Asset, Finite-Lived, Acquired [Table] Variable interest rate Basis spread on interest rate Debt Instrument, Basis Spread on Variable Rate Other Commitments [Domain] Other Commitments [Domain] Loss from unconsolidated real estate ventures, including income distributions Loss from unconsolidated real estate ventures, including income distributions Loss From Real Estate Ventures Net Of Distributions Loss from real estate ventures, net of distributions. City Area Code City Area Code Variable Rate [Domain] Variable Rate [Domain] Repayments of unsecured notes Repayments Of Unsecured Notes Payables Repayments Of Unsecured Notes Payables Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Document Information [Table] Document Information [Table] All Individuals All Individuals [Member] Interest Rate Swap, 3.629% 3.629% Interest Rate Swap Maturing December 30, 2026 [Member] 3.629% Interest Rate Swap Maturing December 30, 2026 Debt instrument, fair value Debt Instrument, Fair Value Disclosure Common Shares in Grantor Trust Common Stock Held In Trust [Member] Common stock held in trust. Accumulated Amortization Below Market Lease, Accumulated Amortization 8.80% Note 2028 8.80% Note 2028 [Member] 8.80% Note 2028 Name Forgone Recovery, Individual Name Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Distributions declared to general partnership unit holders Partners' Capital Account, Distributions Statement [Line Items] Statement [Line Items] Total assets Assets Entity [Domain] Entity [Domain] Interest and investment income Investment Income, Net Equity funding percentage expected to be funded Limited Payment Guarantee, Percent Of Principle Balance Limited Payment Guarantee, Percent Of Principle Balance Net loss attributable to noncontrolling interests - consolidated real estate ventures Income (Loss) from Continuing Operations, Net of Tax, Attributable to Noncontrolling Interest Equity Method Investment, Nonconsolidated Investee [Domain] Equity Method Investment, Nonconsolidated Investee [Domain] Operating Segments Operating Segments [Member] Total Brandywine Operating Partnership, L.P.'s equity Partners' Capital Payments for repurchase of preferred stock and preference stock Payments for Repurchase of Preferred Stock and Preference Stock Other assets Other assets Increase (Decrease) in Other Operating Assets Organization of the Parent Company and the Operating Partnership Nature of Operations [Text Block] Prepaid ground leases, net Prepaid Ground Leases, Net Prepaid Ground Leases, Net PEO PEO [Member] 2028 Long-Term Debt, Maturity, Year Two Repurchase and retirement of LP units (in shares) Partners Capital Account Units Repurchased And Retired Partners Capital Account Units Repurchased And Retired Measurement Basis Measurement Basis [Axis] Reconciliation of cash and cash equivalents and restricted cash: Reconciliation Of Cash Cash Equivalents And Restricted Cash [Abstract] Reconciliation of cash cash equivalents and restricted cash. Repurchase and retirement of Common Shares of Beneficial Interest (in shares) Repurchased and retired (in shares) Stock Repurchased and Retired During Period, Shares Tenant improvements Tenant Improvements Intangible Assets and Liabilities Intangible Assets And Liabilities Disclosure [Text Block] Intangible assets and liabilities disclosure. Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Liabilities Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract] Intangible assets, net: Intangible Asset, Excluding Goodwill, after Accumulated Amortization [Abstract] Cumulative Earnings Retained Earnings [Member] Operating expenses Operating Expenses Intangible liabilities, net Intangible liabilities, net Below Market Lease, Net, Operating Activities Below Market Lease, Net, Operating Activities Construction loan amount Capital Commitment Targets, Construction Loan Amount Capital Commitment Targets, Construction Loan Amount Open-market Purchase Open-market Purchase [Member] Open-market Purchase Comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Period Change [Abstract] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares outstanding (in shares) Beginning balance (in shares) Ending balance (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Schedule of Financial Instruments with Fair Values Different from their Carrying Amount Fair Value, by Balance Sheet Grouping [Table Text Block] Proceeds from construction loan Proceeds from construction loan Proceeds from Construction Loans Payable Diluted loss per Common Share (in dollars per share) Net loss attributable to common shareholders, diluted (in dollars per share) Earnings Per Share, Diluted Entity Current Reporting Status Entity Current Reporting Status Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Variable lease payments Operating Lease, Variable Lease Income Cash Flow Hedging Cash Flow Hedging [Member] Wholly Owned Properties Wholly Owned Properties [Member] 3151 Market Street 3151 Market Street [Member] 3151 Market Street Ownership Ownership [Domain] Proceeds from credit facility borrowings Proceeds from credit facility borrowings Proceeds from Long-Term Lines of Credit Adjustments to reconcile net income to net cash from operating activities: Adjustments to reconcile net income to net cash from operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] 2029 Long-Term Debt, Maturity, Year Three Pennsylvania Central Business District Pennsylvania Central Business District [Member] Pennsylvania Central Business District Cash flows from financing activities: Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Variable rate debt Variable Rate Debt [Member] Variable rate debt. Partially Owned Properties Partially Owned Properties [Member] Acquisition of real estate investments Payments to Acquire Interest in Joint Venture Schedule of Results of Operations of Real Estate Ventures with Interests Equity Method Investments [Table Text Block] Intangible Asset, Finite-Lived, Class [Axis] Intangible Asset, Finite-Lived, Class [Axis] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Underlying Securities Award Underlying Securities Amount Comprehensive loss attributable to noncontrolling interest Comprehensive loss attributable to noncontrolling interest - consolidated real estate ventures Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Fair Value Estimate of Fair Value Measurement [Member] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Unrealized gain (loss) on derivative financial instruments Unrealized gain (loss) on derivative financial instruments Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, after Tax Redeemable Common Limited Partnership Units Redeemable Common Limited Partnership Units [Member] Redeemable common limited partnership units. Segment Reporting [Table] Segment Reporting [Table] Cumulative Distributions Accumulated Distributions in Excess of Net Income [Member] Interest Rate Cap, 3.000% 3.00% Interest Rate Cap Maturing July 22, 2026 [Member] 3.00% Interest Rate Cap Maturing July 22, 2026 Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-Term Debt [Table Text Block] Equity Method Investment [Table] Equity Method Investment [Table] Schedule of Intangible Assets and Liabilities Schedule Of Finite Lived Intangible Assets And Liabilities Table [Table Text Block] Schedule of finite lived intangible assets and liabilities. Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Operating income (loss) Operating Income (Loss) Current Fiscal Year End Date Current Fiscal Year End Date Unconsolidated Properties Unconsolidated Properties [Member] Impairment of real estate Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Mixed-use Properties Mixed Use Properties [Member] Mixed-use properties. Partners' Equity of the Parent Company Partners' Capital Notes Disclosure [Text Block] Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Distributions declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Office Properties Office Building [Member] Total Real Estate Investment Property Held For Use And Sale Real Estate Investment Property Held For Use And Sale Share-based compensation activity Share-based compensation activity Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Average closing price of the common shares, number of business days Average Closing Price of The Common Shares, Number of Business Days Average Closing Price of The Common Shares, Number of Business Days Interest Rate Swap, 3.959% 3.959% Interest Rate Swap Maturing June 24, 2033 [Member] 3.959% Interest Rate Swap Maturing June 24, 2033 Indenture IA (Preferred Trust I) Indenture Ia Preferred Trust I [Member] Indenture IA (Preferred Trust I). Distributions to Noncontrolling interest holders Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Provision for impairment Provision for impairment Asset, Impairment Loss Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Common stock, shares issued (in shares) Common Stock, Shares, Issued Measure: Measure [Axis] Investment in Unconsolidated Real Estate Ventures Equity Method Investments and Joint Ventures Disclosure [Text Block] Aggregate amount related to non-controlling interests classified within equity Noncontrolling Interest in Operating Partnerships Amortization of debt discount/(premium), net Amortization of debt discount/(premium), net Amortization of Debt Discount (Premium) Construction-in-progress Construction-in-progress Development in Process Increase (Decrease) in Partners' Capital [Roll Forward] Increase (Decrease) in Partners' Capital [Roll Forward] Variable rate debt Loans Payable Leashold Interest Land Leashold Interest Land [Member] Leashold interest land. Debt repaid Debt Instrument, Repaid, Principal Equity Components [Axis] Equity Components [Axis] Accounts receivable Accounts receivable Increase (Decrease) in Accounts Receivable Capital expenditures for tenant improvements Capital expenditures for tenant improvements Payment for Leasehold Improvement, Lessor, Investing Activity Product and Service Product and Service [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Cash paid for income taxes Income Tax Paid, after Refund Received Share Issuance from/(to) Deferred Compensation Plan Deferred compensation obligation Share Issuance From (To) Deferred Compensation Plan Share issuance from/to deferred compensation plan. Derivative asset, fair value, gross asset Interest Rate Fair Value Hedge Asset at Fair Value Entity Interactive Data Current Entity Interactive Data Current Variable Rate [Axis] Variable Rate [Axis] Net loss attributable to noncontrolling interests Net loss attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Rents Rents [Member] Rents. Entity Small Business Entity Small Business Comprehensive loss attributable to Brandywine Realty Trust Comprehensive Income (Loss), Net of Tax, Attributable to Parent Termination Date Trading Arrangement Termination Date Other Commitments [Axis] Other Commitments [Axis] Intangible assets, net Intangible assets, net Finite-Lived Intangible Assets, Net, Continuing Operations Finite-Lived Intangible Assets, Net, Continuing Operations Company's share of net loss Income (Loss) From Equity Method Investments Before Basis Adjustments And Other Income (Loss) From Equity Method Investments Before Basis Adjustments And Other Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Document Type Document Type Earnings Per Common Partnership Unit [Table] Earnings Per Common Partnership Unit [Table] Earnings per Common Partnership Unit. Loss on early extinguishment of debt Loss on early extinguishment of debt Loss on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Fair Value as of Grant Date Award Grant Date Fair Value Debt Covenant Period [Domain] Debt Covenant Period [Domain] Debt Covenant Period [Domain] Operating Activities [Axis] Operating Activities [Axis] Gain on disposition of assets Gain on disposition of assets Gain (Loss) on Disposition of Assets Deferred compensation payable in common shares Deferred Compensation Payable In Common Stock Deferred compensation payable in common stock. Investments by Secondary Categorization Investments Secondary Categorization [Domain] Investments Secondary Categorization Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Arrangement Duration Trading Arrangement Duration Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Consolidation Items Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Extinguishment of debt costs accrued in financing activities Payment for Debt Extinguishment or Debt Prepayment Cost Net loss before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Interest expense Interest expense Interest expense, net Interest expense Interest Expense, Other Commitments and contingencies (See Note 14) Commitments and contingencies (See Note 14) Commitments and Contingencies Total Cost Intangible Asset, Finite-Lived, before Accumulated Amortization Total revenue Revenue Total revenue Revenues Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] 2030 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Four Equity in loss of unconsolidated real estate ventures Equity in loss of unconsolidated real estate ventures Equity in income (loss) of real estate ventures Equity in loss of unconsolidated real estate ventures Income (Loss) from Equity Method Investments Accounts payable and accrued expenses Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Executive Category: Executive Category [Axis] Thereafter Finite-Lived Intangible Asset, Expected Amortization, After Year Four Finite-Lived Intangible Asset, Expected Amortization, After Year Four Unaffiliated Third Party Unaffiliated Third Party [Member] Unaffiliated Third Party $550.0M 8.88% Guaranteed Notes due 2029 8.88% Notes Due 2029 [Member] 8.88% Notes Due 2029 LIABILITIES AND BENEFICIARIES' EQUITY LIABILITIES AND PARTNERS' EQUITY Liabilities and Equity [Abstract] Intangible Asset, Finite-Lived, Class [Domain] Intangible Asset, Finite-Lived, Class [Domain] All Award Types Award Type [Domain] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Multifamily Joint Venture Multifamily Joint Venture [Member] Multifamily Joint Venture Supplemental disclosure: Supplemental disclosure: Supplemental Cash Flow Information [Abstract] 2027 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year One Amortization of acquired above (below) market leases, net Amortization of acquired above (below) market leases, net Amortization of above and below Market Leases Accounts payable and accrued expenses Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities PEO Name PEO Name Redeemable limited partnership units issued (in shares) Temporary Equity, Shares Issued Restricted cash and escrows Restricted cash and escrows Restricted Cash Deferred income, gains and rent Contract with Customer, Liability Long-Lived Asset, Class [Axis] Long-Lived Asset, Class [Axis] Repayments of secured term loan Repayments of Secured Debt Other assets Other assets Other Assets Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Legal Entity [Axis] Legal Entity [Axis] Unsecured notes payable Notes Payable Cash and cash equivalents and restricted cash at beginning of period Cash and cash equivalents and restricted cash at end of period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Fixed contractual payments Operating Lease, Lease Income, Lease Payments Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code 2028 Notes 2028 Notes [Member] 2028 Notes Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Non-NEOs Non-NEOs [Member] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Comprehensive loss Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Equity method investment, ownership percentage Equity Method Investment, Ownership Percentage Amortization of stock compensation costs Amortization of stock compensation costs Share-Based Payment Arrangement, Noncash Expense 2028 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Two Land Land Capitalized interest Interest Paid, Capitalized, Investing Activity Avira Secured Term Loan Avira Secured Term Loan [Member] Avira Secured Term Loan Disposal Group Name [Axis] Disposal Group Name [Axis] Schedule of Consolidated Debt Obligations Schedule of Debt [Table Text Block] Investment, Name [Domain] Investment, Name [Domain] 2027 Long-Term Debt, Maturity, Year One Schedule of Derivative Instruments in Statement of Financial Position, Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Basic loss per Common Share (in dollars per share) Basic loss per Common Partnership Unit (in dollars per share) Net loss attributable to common shareholders, basic (in dollars per share) Earnings Per Share, Basic Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Repurchase and retirement of common shares Payments for Repurchase of Common Stock Statistical Measurement [Axis] Statistical Measurement [Axis] Insider Trading Arrangements [Line Items] Number of unconsolidated investments in real estate ventures Number Of Unconsolidated Investments In Real Estate Ventures Number of unconsolidated investments in Real Estate Ventures. Extinguishment of Debt [Axis] Extinguishment of Debt [Axis] Capital expenditures for developments Capital expenditures for developments Payments to Develop Real Estate Assets Award Type Award Type [Axis] Debt financing costs paid Debt financing costs paid Payments of Financing Costs Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Tender Offer Tender offer [Member] Tender offer Product and Service Product and Service [Axis] Indenture II (Preferred Trust II) Indenture Ii Preferred Trust Ii [Member] Indenture II (Preferred Trust II). Change in capital expenditures financed through accounts payable at period end Change in capital expenditures financed through accounts payable at period end Change In Capital Expenditures Financed Through Accounts Payable At Period End Change in capital expenditures financed through accounts payable. Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Redeemable limited partnership units at redemption value; 515,595 and 515,595 issued and outstanding as of September 30, 2026 and December 31, 2025, respectively Temporary Equity, Including Noncontrolling Interest Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Beneficiaries' Equity of the Parent Company Beneficiaries Equity [Text Block] Beneficiaries' Equity. Common Stock Common Stock [Member] Net gain on disposition of real estate Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Fair Value Measurement Fair Value Measurement [Domain] Schedule of Lease Income Operating Lease, Lease Income [Table Text Block] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Change in capital expenditures financed through retention payable at period end Change in capital expenditures financed through retention payable at period end Change In Capital Expenditures Financed Through Retention Payable At Period End Change in capital expenditures financed through retention payable at period end. Noncontrolling Interest [Abstract] Noncontrolling Interest [Abstract] Commitment funded amount Contractual Obligation, Amount Of Funded Commitment Contractual Obligation, Amount Of Funded Commitment Assets Intangible Asset, Finite-Lived, after Accumulated Amortization, Estimated Amortization Expense, Fiscal Year Maturity [Abstract] Investment in Nonconsolidated Real Estate Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member] Payout ratio Line Of Credit Facility, Funds From Operations, Payout Ratio Line Of Credit Facility, Funds From Operations, Payout Ratio Estimated potential additional contribution obligation Estimated Potential Additional Contribution Obligation Estimated potential additional contribution obligation. Derivative Contract Derivative Contract [Domain] Shares used for employee taxes upon vesting of share awards Shares used for employee taxes upon vesting of share awards Payments On Account Of Employee Tax Withholdings On Share Based Awards Payments on account of employee tax withholdings on share based awards. Equity Awards Adjustments Equity Awards Adjustments [Member] Real Estate Property Ownership Real Estate Property Ownership [Axis] Hedging Relationship Hedging Relationship [Domain] Total liabilities and beneficiaries' equity Liabilities and Equity Interest and investment income Interest and investment income Interest Income, Other Debt Covenant Period 1 Debt Covenant Period 1 [Member] Debt Covenant Period 1 Employee Stock Option Share-Based Payment Arrangement, Option [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Noncontrolling interests Equity, Attributable to Noncontrolling Interest Segments [Axis] Segments [Axis] Other liabilities Other liabilities Increase (Decrease) in Other Operating Liabilities Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Tabular List, Table Tabular List [Table Text Block] Additional paid-in-capital Additional Paid in Capital Rentable area (in square feet) Net Rentable Area 2029 Intangible Asset, Finite-Lived, Estimated Amortization Expense, Year Three 2026 (three months remaining) Intangible Asset, Finite-Lived, Estimated Amortization Expense, Remainder of Fiscal Year Name Awards Close in Time to MNPI Disclosures, Individual Name Real Estate Properties [Line Items] Real Estate Properties [Line Items] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] General and administrative expenses General and administrative expenses General and Administrative Expense Nonforfeitable dividends allocated to unvested restricted shareholders Nonforfeitable dividends allocated to unvested restricted unitholders Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted Long-Lived Asset, Class [Domain] Long-Lived Asset, Class [Domain] Debt Covenant Period 2 Debt Covenant Period 2 [Member] Debt Covenant Period 2 Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Adjustment to Compensation: Adjustment to Compensation [Axis] Number of real estate properties Number of Properties Number of Real Estate Properties $450.0M 3.95% Guaranteed Notes due 2027 3.95% Note 2027 [Member] Note 2027. Office Properties Office Properties [Member] Office Properties. Class of Stock [Domain] Class of Stock [Domain] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Cash paid for interest, net of capitalized interest during the nine months ended September 30, 2026 and 2025 of $1,972 and $9,801, respectively Cash paid for interest, net of capitalized interest during the nine months ended September 30, 2026 and 2025 of $1,972 and $9,801, respectively Interest Paid, Excluding Capitalized Interest, Operating Activity Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Debt retired Extinguishment of Debt, Amount Other commitments Other Commitment Total Cost Below Market Lease, Gross Nonforfeitable dividends allocated to unvested restricted shareholders Nonforfeitable dividends allocated to unvested restricted unitholders Nonforfeitable dividends allocated to unvested restricted shareholders Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Investment in real estate ventures Real Estate Investments, Joint Ventures Common shares in grantor trust, issued and outstanding (in shares) Common Shares In Grantor Trust Issued And Outstanding Common shares in grantor trust issued and outstanding. $350.0M 4.55% Guaranteed Notes due 2029 4.55% Notes 2029 [Member] 4.55% Notes 2029 Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Operating properties Operating properties Real Estate Investment Property, At Cost, Net Of Prepaid Ground Leases Real Estate Investment Property, At Cost, Net Of Prepaid Ground Leases Name Measure Name Development/redevelopment Properties Development And Redevelopment Properties [Member] Development And Redevelopment Properties $600.0M Unsecured Credit Facility $600 Million Unsecured Credit Facility [Member] $600 Million Unsecured Credit Facility Pay vs Performance Disclosure [Line Items] Other Other Operating Segment [Member] Adjustment of redeemable partnership units to liquidation value at period end Adjustment Increase (Decrease) Of Redeemable Partnership Units To Liquidation Value At Period End Adjustment of redeemable partnership units to liquidation value at period end. Debt Instrument [Line Items] Debt Instrument [Line Items] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Name Trading Arrangement, Individual Name Indenture IB (Preferred Trust I) Indenture Ib Preferred Trust I [Member] Indenture IB (Preferred Trust I). Cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash and cash equivalents Cash and Cash Equivalent General Partner Capital General Partner [Member] Net loss attributable to Brandywine Operating Partnership, L.P. Net Income (Loss) Allocated to Limited Partners Company Selected Measure Amount Company Selected Measure Amount Total gain on sale of real estate Gain on Sale of Real Estate Gain on Sale of Real Estate Schedule of Reconciliation of Consolidated Net Income to Consolidated NOI Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block] Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] SOFR Secured Overnight Financing Rate (SOFR) [Member] Intangible Liabilities, net Below Market Lease, Net Entity Address, Address Line Two Entity Address, Address Line Two Share-based compensation activity (in shares) Shares Issued, Shares, Share-Based Payment Arrangement, after Forfeiture Land held for development Land held for development Land Available for Development Stock, Class of Stock [Table] Stock, Class of Stock [Table] Net loss Net loss Net loss Net loss Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Real Estate [Abstract] Real Estate [Abstract] Statement of Partners' Capital [Abstract] Statement of Partners' Capital [Abstract] Brandywine Operating Partnership, L.P. Brandywine Operating Partnership, L.P. [Member] Brandywine Operating Partnership, L.P. Non-PEO NEO Non-PEO NEO [Member] Unsecured senior notes, net Senior Notes [Member] Entity Address, Address Line One Entity Address, Address Line One Income tax provision Income tax provision Income Tax Expense (Benefit) Cumulative earnings Cumulative Earnings (Deficit) Award Timing Method Award Timing Method [Text Block] Drexel Square Drexel Square [Member] Drexel Square. Increase/(Decrease) in cash and cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Core Properties Core Properties [Member] Core Properties [Member] Proceeds from unsecured notes Proceeds from Unsecured Notes Payable Derivative liability, notional amount Derivative Liability, Notional Amount Basis adjustments and other Basis Adjustments And Other Basis Adjustments And Other Net loss attributable to Brandywine Realty Trust Net Income (Loss) Attributable to Parent Interest Rate Swap, 3.725% 3.725% Interest Rate Swap Maturing January 30, 2027 [Member] Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Proceeds from the sale of properties Proceeds from Sale of Property, Plant, and Equipment Statement [Table] Statement [Table] Above market leases acquired Above Market Leases [Member] Restatement Determination Date: Restatement Determination Date [Axis] 3151 Market C-PACE Loan 3151 Market C-PACE Loan [Member] 3151 Market C-PACE Loan Land Held For Development Land Held For Development [Member] Land held for development. Revenue Revenue Revenues [Abstract] Basis of Presentation Basis of Presentation and Significant Accounting Policies [Text Block] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Third party management fees, labor reimbursement and leasing Third Party Management Revenue [Member] Third party management revenue.