Organization	12 Months Ended
Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Equity Commonwealth is a real estate investment trust, or REIT, formed in 1986 under the laws of the State of Maryland. Our primary business is the ownership and operation of real estate, primarily office buildings, throughout the United States. On November 10, 2016, Equity Commonwealth (the Company) converted to what is commonly referred to as an umbrella partnership real estate investment trust, or UPREIT, structure. In connection with this conversion, the Company contributed substantially all of its assets to EQC Operating Trust, a Maryland real estate investment trust through which the Company will conduct its business (the Operating Trust), and the Operating Trust assumed substantially all of the Company’s liabilities pursuant to a contribution and assignment agreement between the Company and the Operating Trust. The Company now conducts and intends to continue to conduct substantially all of its activities through the Operating Trust. The Company beneficially owned, directly and indirectly, 100.0% of the outstanding shares of beneficial interest, designated as units, in the Operating Trust (OP Units) as of December 31, 2016 and the Company is the sole trustee of the Operating Trust. As the sole trustee, the Company generally has the exclusive power under the declaration of trust of the Operating Trust to manage and conduct the business of the Operating Trust, subject to certain limited approval and voting rights of other holders of OP Units that may be admitted in the future. At December 31, 2016, our portfolio included 33 properties (64 buildings), one land parcel and one property taken out of service which is now classified as a land parcel, with a combined 16.1 million square feet. All numbers of properties, numbers of buildings and square feet are unaudited.

Organization

12 Months Ended

Dec. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Equity Commonwealth is a real estate investment trust, or REIT, formed in 1986 under the laws of the State of Maryland. Our primary business is the ownership and operation of real estate, primarily office buildings, throughout the United States.

On November 10, 2016, Equity Commonwealth (the Company) converted to what is commonly referred to as an umbrella partnership real estate investment trust, or UPREIT, structure. In connection with this conversion, the Company contributed substantially all of its assets to EQC Operating Trust, a Maryland real estate investment trust through which the Company will conduct its business (the Operating Trust), and the Operating Trust assumed substantially all of the Company’s liabilities pursuant to a contribution and assignment agreement between the Company and the Operating Trust.

The Company now conducts and intends to continue to conduct substantially all of its activities through the Operating Trust. The Company beneficially owned, directly and indirectly, 100.0% of the outstanding shares of beneficial interest, designated as units, in the Operating Trust (OP Units) as of December 31, 2016 and the Company is the sole trustee of the Operating Trust. As the sole trustee, the Company generally has the exclusive power under the declaration of trust of the Operating Trust to manage and conduct the business of the Operating Trust, subject to certain limited approval and voting rights of other holders of OP Units that may be admitted in the future.

At December 31, 2016, our portfolio included 33 properties (64 buildings), one land parcel and one property taken out of service which is now classified as a land parcel, with a combined 16.1 million square feet. All numbers of properties, numbers of buildings and square feet are unaudited.