Real Estate Properties - Unconsolidated Joint Ventures (Details) ft² in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) ft² joint_venture property	Dec. 31, 2020 USD ($) ft²
Real Estate [Line Items]
Number of joint ventures \| joint_venture	2
Number of properties (in properties) \| property	178
Rentable Square Feet (in square feet) \| ft²	926	163
Unconsolidated Joint Ventures
Real Estate [Line Items]
Number of joint ventures \| joint_venture	2
Number of properties (in properties) \| property	3
OPI Carrying Value of Investments	$ 34,838	$ 37,951
Rentable Square Feet (in square feet) \| ft²	444
Equity method investment, difference between carrying amount and underlying equity	$ 6,977
Unconsolidated Joint Ventures \| Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)	3.93%
Principal balance	$ 82,000	82,000
Unconsolidated Joint Ventures \| Prosperity Metro Plaza
Real Estate [Line Items]
Number of properties (in properties) \| property	2
OPI Ownership	51.00%
OPI Carrying Value of Investments	$ 20,672	21,888
Rentable Square Feet (in square feet) \| ft²	329
Unconsolidated Joint Ventures \| Prosperity Metro Plaza \| Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)	4.09%
Principal balance	$ 50,000	50,000
Unconsolidated Joint Ventures \| 1750 H Street, NW
Real Estate [Line Items]
Number of properties (in properties) \| property	1
OPI Ownership	50.00%
OPI Carrying Value of Investments	$ 14,166	16,063
Rentable Square Feet (in square feet) \| ft²	115
Unconsolidated Joint Ventures \| 1750 H Street, NW \| Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)	3.69%
Principal balance	$ 32,000	$ 32,000

Number Of Joint Ventures

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- Definition

Area of a real estate property.

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Face (par) amount of debt instrument at time of issuance.

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

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- Definition

Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

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

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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.

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