Organization of the Parent Company and The Operating Partnership	9 Months Ended
Sep. 30, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]
ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP	1. ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP The Parent Company is a self-administered and self-managed real estate investment trust (“REIT”) that provides leasing, property management, development, redevelopment, acquisition and other tenant-related services for a portfolio of office, residential, flexible stay, retail and mixed-use properties. The Parent Company owns its assets and conducts its operations through the Operating Partnership and subsidiaries of the Operating Partnership. The Parent Company is the sole general partner of the Operating Partnership and, as of September 30, 2017, owned a 99.2% interest in the Operating Partnership. The Parent Company’s common shares of beneficial interest are publicly traded on the New York Stock Exchange under the ticker symbol “BDN”. As of September 30, 2017, the Company owned 97 properties that contain an aggregate of approximately 16.4 million net rentable square feet and consist of 82 office properties, four mixed-use properties, one retail property (87 properties, collectively the “Core Properties”), one development property, three redevelopment properties and six properties classified as held for sale (collectively, the “Properties”). In addition, as of September 30, 2017, the Company owned economic interests in 13 unconsolidated real estate ventures (collectively, the “Real Estate Ventures”), seven of which own properties that contain an aggregate of approximately 7.8 million net rentable square feet of office space; four of which own, in aggregate, 5.7 acres of land held for development and two of which own residential towers that contain 345 and 321 apartment units, respectively. As of September 30, 2017, the Company also owned 214 acres of undeveloped land and held options to purchase approximately 60 additional acres of undeveloped land. As of September 30, 2017, the total potential development that these land parcels could support, including the parcels under option, amounted to an estimated 15.7 million square feet. The Properties and the properties owned by the Real Estate Ventures are located in or near Philadelphia, Pennsylvania; Metropolitan Washington, D.C.; Southern New Jersey; Wilmington, Delaware and Austin, Texas. In addition to managing properties owned by the Company, as of September 30, 2017, the Company was managing approximately 10.0 million net rentable square feet of office and industrial properties for third parties and Real Estate Ventures. The Company conducts its third-party real estate management services business primarily through wholly-owned management company subsidiaries. As of September 30, 2017, the management company subsidiaries were managing properties containing an aggregate of approximately 26.4 million net rentable square feet, of which approximately 16.4 million net rentable square feet related to Properties owned by the Company and approximately 10.0 million net rentable square feet related to properties owned by third parties and Real Estate Ventures. Unless otherwise indicated, all references in this Form 10-Q to square feet represent net rentable area.

1. ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP

The Parent Company is a self-administered and self-managed real estate investment trust (“REIT”) that provides leasing, property management, development, redevelopment, acquisition and other tenant-related services for a portfolio of office, residential, flexible stay, retail and mixed-use properties. The Parent Company owns its assets and conducts its operations through the Operating Partnership and subsidiaries of the Operating Partnership. The Parent Company is the sole general partner of the Operating Partnership and, as of September 30, 2017, owned a 99.2% interest in the Operating Partnership. The Parent Company’s common shares of beneficial interest are publicly traded on the New York Stock Exchange under the ticker symbol “BDN”.

As of September 30, 2017, the Company owned 97 properties that contain an aggregate of approximately 16.4 million net rentable square feet and consist of 82 office properties, four mixed-use properties, one retail property (87 properties, collectively the “Core Properties”), one development property, three redevelopment properties and six properties classified as held for sale (collectively, the “Properties”). In addition, as of September 30, 2017, the Company owned economic interests in 13 unconsolidated real estate ventures (collectively, the “Real Estate Ventures”), seven of which own properties that contain an aggregate of approximately 7.8 million net rentable square feet of office space; four of which own, in aggregate, 5.7 acres of land held for development and two of which own residential towers that contain 345 and 321 apartment units, respectively. As of September 30, 2017, the Company also owned 214 acres of undeveloped land and held options to purchase approximately 60 additional acres of undeveloped land. As of September 30, 2017, the total potential development that these land parcels could support, including the parcels under option, amounted to an estimated 15.7 million square feet. The Properties and the properties owned by the Real Estate Ventures are located in or near Philadelphia, Pennsylvania; Metropolitan Washington, D.C.; Southern New Jersey; Wilmington, Delaware and Austin, Texas. In addition to managing properties owned by the Company, as of September 30, 2017, the Company was managing approximately 10.0 million net rentable square feet of office and industrial properties for third parties and Real Estate Ventures.

The Company conducts its third-party real estate management services business primarily through wholly-owned management company subsidiaries. As of September 30, 2017, the management company subsidiaries were managing properties containing an aggregate of approximately 26.4 million net rentable square feet, of which approximately 16.4 million net rentable square feet related to Properties owned by the Company and approximately 10.0 million net rentable square feet related to properties owned by third parties and Real Estate Ventures.

Unless otherwise indicated, all references in this Form 10-Q to square feet represent net rentable area.