Subsequent Events	12 Months Ended
Dec. 31, 2015
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	21. SUBSEQUENT EVENTS 30^th Street Main Post Office Sale On February 5, 2016, the Company completed the disposition of its equity interests in the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30^th Street Main Post Office (“Cira Square”), for a gross sales price of $354.0 million. Cira Square, which contains 862,692 net rentable square feet of office space and is fully leased to a single tenant, was encumbered by mortgage indebtedness at December 31, 2015 (referred to in Note 7, “Debt Obligations,” as IRS Philadelphia Campus – Mortgage Debt). After the payment of $3.7 million of closings costs at settlement, the Company received net proceeds of $350.3 million and recognized a gain on sale of $113.4 million. On January 14, 2016, the Company funded $221.4 million, consisting of $176.8 million of principal repayment, $44.5 million in prepayment charges and $0.1 million of accrued interest, in repayment of the mortgage indebtedness of Cira Square, ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.5 million, consisting of $35.4 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of the Cira South Garage, ahead of its scheduled maturity date of September 10, 2030. The repayment was financed with funds available under the unsecured revolving credit facility. Additionally, the Company recognized a loss on extinguishment of debt in the amount of $13.2 million related to a non-cash charge for deferred financing costs. The Company intends to use the net proceeds from the Cira Square sale, net of the early mortgage payoffs, to reduce debt, fund current development commitments and for general corporate purposes. The transaction agreements provide for the purchaser to engage the Company’s management company subsidiary to provide customary property management services for the property with an annual management fee (exclusive of expense reimbursement) not to exceed 1.5% of annual gross revenues of the property. The Company’s agreement is for a ten-year term, subject to early termination by the purchaser in the event that the Company fails to fulfill its obligations at any time during the term of the agreement or upon sale by the purchaser of the property. If the purchaser terminates the agreement within seven years of the management agreement commencement date the Company shall be entitled to a termination fee in an amount equal to the management fee that would have been paid to the Company for the remainder of the seven-year term had such termination not occurred. Och Ziff Sale On February 4, 2016, the Company received $353.4 million in cash proceeds from a series of related transactions with affiliates of Och Ziff Capital Management Group LLC (“Och Ziff”) that resulted in the disposition of 58 properties that contain an aggregate of 3,924,783 square feet. The properties are located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments. The transactions involved: (i) the sale to MAP Fee Owner LLC, an affiliate of Och-Ziff (the “O-Z Land Purchaser”), 100% of the Company’s fee interests in the land parcels (the “Land Parcels”) underlying the office properties, together with rights to be the lessor under long-term ground leases (the “Ground Leases”) covering the Land Parcels; (ii) the Company’s formation of a joint venture (the “Venture”) with MAP Ground Lease Owner LLC, an affiliate of Och-Ziff (the “O-Z Venture Partner”), and the Company’s sale to the Venture of the office buildings and related improvements (the “Buildings”) situated on the Land Parcels; and (iii) the retention of a non-controlling equity interest in the Venture. The transaction agreements provide for the Venture to engage a subsidiary of the Company to provide customary property management services in an amount equal to 2.5% of gross rental receipts. The initial term is through December 31, 2016 and is renewed automatically each year unless terminated. The Company may be terminated without cause, subject to a ninety day notification. The Company intends to use the net cash proceeds that it received in the transaction for general corporate purposes, including to reduce its outstanding debt and fund current development commitments. Based upon the facts and circumstances at formation of the Venture, the Company determined that the Venture is a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company used the variable interest model under the accounting standard for consolidation in order to determine whether to consolidate the Venture. Based upon each member’s power to control the activities that most significantly impact the economics of the Venture under the operating and related agreements of the Venture, it is accounted for under the equity method of accounting. Reportable Segments During the year ended December 31, 2015, the Company was managing its portfolio within seven segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C., (4) New Jersey/Delaware, (5) Richmond, Virginia, (6) Austin, Texas and (7) California. As a result of the Och Ziff Sale that occurred on February 4, 2016, the Company has narrowed its segments to four core markets located in: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas. The Och Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och Ziff Sale, the segments previously defined as New Jersey/Delaware and California will be managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker is revising the management structure and allocating more resources to the four core markets beginning January 1, 2016. The Company has evaluated subsequent events through the date the financial statements were issued.

21. SUBSEQUENT EVENTS

30^th Street Main Post Office Sale

On February 5, 2016, the Company completed the disposition of its equity interests in the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30^th Street Main Post Office (“Cira Square”), for a gross sales price of $354.0 million. Cira Square, which contains 862,692 net rentable square feet of office space and is fully leased to a single tenant, was encumbered by mortgage indebtedness at December 31, 2015 (referred to in Note 7, “Debt Obligations,” as IRS Philadelphia Campus – Mortgage Debt). After the payment of $3.7 million of closings costs at settlement, the Company received net proceeds of $350.3 million and recognized a gain on sale of $113.4 million.

On January 14, 2016, the Company funded $221.4 million, consisting of $176.8 million of principal repayment, $44.5 million in prepayment charges and $0.1 million of accrued interest, in repayment of the mortgage indebtedness of Cira Square, ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.5 million, consisting of $35.4 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of the Cira South Garage, ahead of its scheduled maturity date of September 10, 2030. The repayment was financed with funds available under the unsecured revolving credit facility. Additionally, the Company recognized a loss on extinguishment of debt in the amount of $13.2 million related to a non-cash charge for deferred financing costs. The Company intends to use the net proceeds from the Cira Square sale, net of the early mortgage payoffs, to reduce debt, fund current development commitments and for general corporate purposes.

The transaction agreements provide for the purchaser to engage the Company’s management company subsidiary to provide customary property management services for the property with an annual management fee (exclusive of expense reimbursement) not to exceed 1.5% of annual gross revenues of the property. The Company’s agreement is for a ten-year term, subject to early termination by the purchaser in the event that the Company fails to fulfill its obligations at any time during the term of the agreement or upon sale by the purchaser of the property. If the purchaser terminates the agreement within seven years of the management agreement commencement date the Company shall be entitled to a termination fee in an amount equal to the management fee that would have been paid to the Company for the remainder of the seven-year term had such termination not occurred.

Och Ziff Sale

On February 4, 2016, the Company received $353.4 million in cash proceeds from a series of related transactions with affiliates of Och Ziff Capital Management Group LLC (“Och Ziff”) that resulted in the disposition of 58 properties that contain an aggregate of 3,924,783 square feet. The properties are located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments. The transactions involved: (i) the sale to MAP Fee Owner LLC, an affiliate of Och-Ziff (the “O-Z Land Purchaser”), 100% of the Company’s fee interests in the land parcels (the “Land Parcels”) underlying the office properties, together with rights to be the lessor under long-term ground leases (the “Ground Leases”) covering the Land Parcels; (ii) the Company’s formation of a joint venture (the “Venture”) with MAP Ground Lease Owner LLC, an affiliate of Och-Ziff (the “O-Z Venture Partner”), and the Company’s sale to the Venture of the office buildings and related improvements (the “Buildings”) situated on the Land Parcels; and (iii) the retention of a non-controlling equity interest in the Venture.

The transaction agreements provide for the Venture to engage a subsidiary of the Company to provide customary property management services in an amount equal to 2.5% of gross rental receipts. The initial term is through December 31, 2016 and is renewed automatically each year unless terminated. The Company may be terminated without cause, subject to a ninety day notification.

The Company intends to use the net cash proceeds that it received in the transaction for general corporate purposes, including to reduce its outstanding debt and fund current development commitments.

Based upon the facts and circumstances at formation of the Venture, the Company determined that the Venture is a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company used the variable interest model under the accounting standard for consolidation in order to determine whether to consolidate the Venture. Based upon each member’s power to control the activities that most significantly impact the economics of the Venture under the operating and related agreements of the Venture, it is accounted for under the equity method of accounting.

Reportable Segments

During the year ended December 31, 2015, the Company was managing its portfolio within seven segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C., (4) New Jersey/Delaware, (5) Richmond, Virginia, (6) Austin, Texas and (7) California. As a result of the Och Ziff Sale that occurred on February 4, 2016, the Company has narrowed its segments to four core markets located in: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas. The Och Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och Ziff Sale, the segments previously defined as New Jersey/Delaware and California will be managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker is revising the management structure and allocating more resources to the four core markets beginning January 1, 2016.

The Company has evaluated subsequent events through the date the financial statements were issued.