Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation	The accompanying condensed consolidated financial statements of Office Properties Income Trust and its subsidiaries, or OPI, we, us or our, are unaudited. Certain information and disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes contained in our Annual Report on Form 10-K for the year ended December 31, 2024, or our 2024 Annual Report. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair statement of results for the interim period have been included. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Our operating results for interim periods are not necessarily indicative of the results that may be expected for the full year.
Basis of Presentation	The preparation of these financial statements in conformity with GAAP requires us to make estimates and assumptions that affect reported amounts. Actual results could differ from those estimates. Significant estimates in the condensed consolidated financial statements include purchase price allocations, useful lives of fixed assets and assessment of impairment of real estate and the related intangibles.
Bankruptcy Accounting	Bankruptcy Accounting The accompanying unaudited condensed consolidated financial statements do not reflect the effects of the Chapter 11 Cases. Effective on the Petition Date, we began applying Financial Accounting Standards Board Accounting Standards Codification Topic 852, Reorganizations, or ASC 852, which specifies the accounting and financial reporting requirements for entities reorganizing through Chapter 11 bankruptcy proceedings. These requirements include distinguishing certain liabilities subject to compromise, or LSTC, in the condensed consolidated balance sheet. In addition, the condensed consolidated statement of comprehensive income (loss) must distinguish transactions directly associated with the reorganization separately as reorganization items, net. These items include the write off of unamortized discounts, premiums and issuance costs related to debt classified as LSTC, which amounted to $25,429 as of the Petition Date. We did not meet the conditions for the application of ASC 852 as of September 30, 2025, as the Chapter 11 Cases occurred subsequent to that date. Upon emergence from bankruptcy on the effective date of the Plan, we expect to qualify for fresh-start reporting. In order to qualify for fresh-start reporting (i) the holders of existing voting shares of OPI prior to its emergence must receive less than 50% of the outstanding voting shares of the reorganized company following its emergence from bankruptcy and (ii) the reorganization value of OPI’s assets immediately prior to confirmation of the Plan must be less than the post-petition liabilities and allowed claims. Under the principles of fresh-start reporting, a new reporting entity, or the Successor, will be considered to have been created, and, as a result, the Successor will allocate the reorganization value of the Successor to its individual assets based on their estimated fair values.
Per Common Share Amounts	We calculate basic earnings per common share using the two class method. We calculate diluted earnings per common share using the more dilutive of the two class method or the treasury stock method. Unvested share awards and other potentially dilutive common shares, together with the related impact on earnings, are considered when calculating diluted earnings per common share.
Real Estate Properties	We regularly evaluate whether events or changes in circumstances have occurred that could indicate an impairment in the value of long lived assets. Impairment indicators may include declining tenant occupancy, lack of progress re-leasing vacant space, tenant bankruptcies, low long term prospects for improvement in property performance, weak or declining tenant profitability, cash flow or liquidity, our decision to dispose of an asset before the end of its estimated useful life and legislative, market or industry changes that could permanently reduce the value of a property. If there is an indication that the carrying value of an asset is not recoverable, we estimate the projected undiscounted cash flows to determine if an impairment loss should be recognized. The future net undiscounted cash flows are subjective and are based in part on assumptions regarding hold periods, market rents and terminal capitalization rates. We determine the amount of any impairment loss by comparing the historical carrying value to estimated fair value. We estimate fair value through an evaluation of recent financial performance and projected discounted cash flows using standard industry valuation techniques. In addition to consideration of impairment upon the events or changes in circumstances described above, we regularly evaluate the remaining useful lives of our long lived assets. If we change our estimate of the remaining useful lives, we allocate the carrying value of the affected assets over their revised remaining useful lives.
Revenue Recognition	Our leases provide for base rent payments and, in addition, may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term once we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. Allowances for bad debts are recognized as a direct reduction of rental income. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its lease obligations; we have determined the fixed non-cancelable lease term of these leases to be the full term of the lease because we believe the occurrence of early terminations to be a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis.

Basis of Presentation (Policies)

9 Months Ended

Sep. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The accompanying condensed consolidated financial statements of Office Properties Income Trust and its subsidiaries, or OPI, we, us or our, are unaudited. Certain information and disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes contained in our Annual Report on Form 10-K for the year ended December 31, 2024, or our 2024 Annual Report. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair statement of results for the interim period have been included. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Our operating results for interim periods are not necessarily indicative of the results that may be expected for the full year.

Basis of Presentation

The preparation of these financial statements in conformity with GAAP requires us to make estimates and assumptions that affect reported amounts. Actual results could differ from those estimates. Significant estimates in the condensed consolidated financial statements include purchase price allocations, useful lives of fixed assets and assessment of impairment of real estate and the related intangibles.

Bankruptcy Accounting

The accompanying unaudited condensed consolidated financial statements do not reflect the effects of the Chapter 11 Cases. Effective on the Petition Date, we began applying Financial Accounting Standards Board Accounting Standards Codification Topic 852, Reorganizations, or ASC 852, which specifies the accounting and financial reporting requirements for entities reorganizing through Chapter 11 bankruptcy proceedings. These requirements include distinguishing certain liabilities subject to compromise, or LSTC, in the condensed consolidated balance sheet. In addition, the condensed consolidated statement of comprehensive income (loss) must distinguish transactions directly associated with the reorganization separately as reorganization items, net. These items include the write off of unamortized discounts, premiums and issuance costs related to debt classified as LSTC, which amounted to $25,429 as of the Petition Date. We did not meet the conditions for the application of ASC 852 as of September 30, 2025, as the Chapter 11 Cases occurred subsequent to that date.

Upon emergence from bankruptcy on the effective date of the Plan, we expect to qualify for fresh-start reporting. In order to qualify for fresh-start reporting (i) the holders of existing voting shares of OPI prior to its emergence must receive less than 50% of the outstanding voting shares of the reorganized company following its emergence from bankruptcy and (ii) the reorganization value of OPI’s assets immediately prior to confirmation of the Plan must be less than the post-petition liabilities and allowed claims. Under the principles of fresh-start reporting, a new reporting entity, or the Successor, will be considered to have been created, and, as a result, the Successor will allocate the reorganization value of the Successor to its individual assets based on their estimated fair values.

Per Common Share Amounts

We calculate basic earnings per common share using the two class method. We calculate diluted earnings per common share using the more dilutive of the two class method or the treasury stock method. Unvested share awards and other potentially dilutive common shares, together with the related impact on earnings, are considered when calculating diluted earnings per common share.

Real Estate Properties

We regularly evaluate whether events or changes in circumstances have occurred that could indicate an impairment in the value of long lived assets. Impairment indicators may include declining tenant occupancy, lack of progress re-leasing vacant space, tenant bankruptcies, low long term prospects for improvement in property performance, weak or declining tenant profitability, cash flow or liquidity, our decision to dispose of an asset before the end of its estimated useful life and legislative, market or industry changes that could permanently reduce the value of a property. If there is an indication that the carrying value of an asset is not recoverable, we estimate the projected undiscounted cash flows to determine if an impairment loss should be recognized. The future net undiscounted cash flows are subjective and are based in part on assumptions regarding hold periods, market rents and terminal capitalization rates. We determine the amount of any impairment loss by comparing the historical carrying value to estimated fair value. We estimate fair value through an evaluation of recent financial performance and projected discounted cash flows using standard industry valuation techniques. In addition to consideration of impairment upon the events or changes in circumstances described above, we regularly evaluate the remaining useful lives of our long lived assets. If we change our estimate of the remaining useful lives, we allocate the carrying value of the affected assets over their revised remaining useful lives.

Revenue Recognition

Our leases provide for base rent payments and, in addition, may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term once we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. Allowances for bad debts are recognized as a direct reduction of rental income. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its lease obligations; we have determined the fixed non-cancelable lease term of these leases to be the full term of the lease because we believe the occurrence of early terminations to be a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis.