Number of Mortgage Notes

No definition available.

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Namespace Prefix:	opi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Period Type:	instant

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of real estate properties owned as of the balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

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Balance Type:	credit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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Balance Type:	credit
Period Type:	instant

- Details

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- Details

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- Details

Name:	us-gaap_DebtInstrumentAxis=opi_A3700MortgageNotesPayableMember
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- Details

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- Details

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Fair Value of Assets and Liabilities - Financial Instruments (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Jun. 30, 2023 USD ($) mortgage_note property	Jun. 30, 2023 USD ($) mortgage_note property	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Fair Value of Financial Instruments
Senior notes	$ 2,191,676	$ 2,191,676		$ 2,187,875
Mortgage notes payable	$ 106,365	106,365		49,917
Repayment of mortgage notes payable		$ 50,000	$ 25,283
Number of mortgage notes \| mortgage_note	4	4
4.25% Senior Unsecured Notes Due 2024
Fair Value of Financial Instruments
Interest rate (as a percent)	4.25%	4.25%
4.50% Senior Unsecured Notes Due 2025
Fair Value of Financial Instruments
Interest rate (as a percent)	4.50%	4.50%
2.650% Senior Unsecured Notes Due 2026
Fair Value of Financial Instruments
Interest rate (as a percent)	2.65%	2.65%
2.400% Senior Unsecured Notes Due 2027
Fair Value of Financial Instruments
Interest rate (as a percent)	2.40%	2.40%
3.450% Senior Unsecured Notes Due 2031
Fair Value of Financial Instruments
Interest rate (as a percent)	3.45%	3.45%
6.375% Senior Unsecured Notes Due 2050
Fair Value of Financial Instruments
Interest rate (as a percent)	6.375%	6.375%
3.700% Mortgage Notes Payable
Fair Value of Financial Instruments
Number of properties (in properties) \| property	1	1
Mortgages
Fair Value of Financial Instruments
Interest rate (as a percent)	7.863%	7.863%
Outstanding principal amount	$ 108,120	$ 108,120
Mortgages \| 3.700% Mortgage Notes Payable
Fair Value of Financial Instruments
Interest rate (as a percent)	3.70%	3.70%
Repayment of mortgage notes payable	$ 50,000
Senior Notes And Mortgages
Fair Value of Financial Instruments
Unamortized debt premiums, discounts and issuance costs	22,079	$ 22,079		24,208
Carrying Value
Fair Value of Financial Instruments
Fair value of financial instruments	2,298,041	2,298,041		2,237,792
Carrying Value \| 4.25% Senior Unsecured Notes Due 2024
Fair Value of Financial Instruments
Senior notes	348,004	348,004		346,863
Carrying Value \| 4.50% Senior Unsecured Notes Due 2025
Fair Value of Financial Instruments
Senior notes	644,542	644,542		642,818
Carrying Value \| 2.650% Senior Unsecured Notes Due 2026
Fair Value of Financial Instruments
Senior notes	298,151	298,151		297,839
Carrying Value \| 2.400% Senior Unsecured Notes Due 2027
Fair Value of Financial Instruments
Senior notes	347,776	347,776		347,466
Carrying Value \| 3.450% Senior Unsecured Notes Due 2031
Fair Value of Financial Instruments
Senior notes	396,396	396,396		396,178
Carrying Value \| 6.375% Senior Unsecured Notes Due 2050
Fair Value of Financial Instruments
Senior notes	156,807	156,807		156,711
Carrying Value \| Mortgages
Fair Value of Financial Instruments
Mortgage notes payable	106,365	106,365		49,917
Fair Value
Fair Value of Financial Instruments
Fair value of financial instruments	1,749,333	1,749,333		1,840,543
Fair Value \| 4.25% Senior Unsecured Notes Due 2024
Fair Value of Financial Instruments
Senior notes	330,082	330,082		331,601
Fair Value \| 4.50% Senior Unsecured Notes Due 2025
Fair Value of Financial Instruments
Senior notes	561,672	561,672		589,388
Fair Value \| 2.650% Senior Unsecured Notes Due 2026
Fair Value of Financial Instruments
Senior notes	221,097	221,097		232,770
Fair Value \| 2.400% Senior Unsecured Notes Due 2027
Fair Value of Financial Instruments
Senior notes	235,344	235,344		256,606
Fair Value \| 3.450% Senior Unsecured Notes Due 2031
Fair Value of Financial Instruments
Senior notes	210,204	210,204		268,004
Fair Value \| 6.375% Senior Unsecured Notes Due 2050
Fair Value of Financial Instruments
Senior notes	79,704	79,704		113,075
Fair Value \| Mortgages
Fair Value of Financial Instruments
Mortgage notes payable	$ 111,230	$ 111,230		$ 49,099