COMMITMENTS AND CONTINGENCIES	12 Months Ended
COMMITMENTS AND CONTINGENCIES	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	20. COMMITMENTS AND CONTINGENCIES Legal Proceedings The Company is involved from time to time in litigation on various matters, including disputes with tenants, disputes with vendors, employee disputes and disputes arising out of agreements to purchase or sell properties or joint ventures or disputes relating to state and local taxes. Given the nature of the Company’s business activities, these lawsuits are considered routine to the conduct of its business. The result of any particular lawsuit cannot be predicted, because of the very nature of litigation, the litigation process and its adversarial nature, and the jury system. The Company will establish reserves for specific legal proceedings when it determines that the likelihood of an unfavorable outcome is probable and when the amount of loss is reasonably estimable. The Company does not expect that the liabilities, if any, that may ultimately result from such legal actions will have a material adverse effect on the consolidated financial position, results of operations or cash flows of the Company. Environmental As an owner of real estate, the Company is subject to various environmental laws of federal, state, and local governments. The Company’s compliance with existing laws has not had a material adverse effect on its financial condition and results of operations, and the Company does not believe it will have a material adverse effect in the future. However, the Company cannot predict the impact of unforeseen environmental contingencies or new or changed laws or regulations on its current Properties or on properties that the Company may acquire. Debt Guarantees As of December 31, 2022, the Company's unconsolidated real estate ventures had aggregate indebtedness of $1,204.8 million. These loans are generally mortgage or construction loans, most of which are nonrecourse to the Company, except for customary recourse carve-outs. In addition, during construction undertaken by the unconsolidated real estate ventures, including the 3025 JFK Venture, the Company has provided, and expects to continue to provide, cost overrun and completion guarantees, as well as customary environmental indemnities and guarantees of customary exceptions to nonrecourse provisions in loan agreements. In the agreement with its partner in the 3025 JFK Venture, the Company agreed to provide cost overrun and completion guaranties for the project under development. With respect to the construction loan obtained by 3025 JFK Venture on July 23, 2021, the Company has also provided a carry guarantee and limited payment guarantee up to 25% of the principal balance of the $186.7 million construction loan. The Company has also provided cost overrun and completion guarantees, as well as customary environmental indemnities, in favor of the joint venture partners, for the One Uptown Ventures. See also Note 4, “Investment in Unconsolidated Real Estate Ventures,” for information on the guarantees in favor of the lenders on the construction loans for the One Uptown Ventures. Impact of Natural Disasters and Casualty The Company carries liability insurance to mitigate its exposure to certain losses, including those relating to property damage. The Company records the estimated amount of expected insurance proceeds for property damage and other losses incurred as an asset (typically a receivable from the insurer) and income up to the amount of the losses incurred when receipt of insurance proceeds is deemed probable. Any amount of insurance recovery in excess of the amount of the losses is considered a gain contingency and is not recorded until the proceeds are received. In February 2021, one of the Company's properties in Austin, Texas sustained damage from the winter storms and resulting power grid failures. As a result of the damage, during the year ended December 31, 2021, the Company recorded a fixed asset write-off totaling $1.2 million. During the year ended December 31, 2021, the Company has recorded an estimated $7.2 million of restoration costs, of which $1.9 million is included in Accounts payable and accrued expenses on the consolidated balance sheets as of December 31, 2021. The Company has also sustained business interruption loss of $3.9 million related to unpaid rent, which is also fully covered under the insurance policy. During the year ended December 31, 2021, the Company received $15.3 million of insurance proceeds, resulting in full recovery of the costs incurred to date. The $3.0 million of insurance proceeds received in excess of the fixed asset write-off, total business interruption, and total estimated restoration cost during the year ended December 31, 2021 is included in Other income on the consolidated statement of operations. During year ended December 31, 2022, the Company recognized a $0.8 million reduction of the previously estimated restoration costs and also received $2.8 million of additional insurance proceeds. The reduction of the restoration costs and additional insurance proceeds are included in other income on the consolidated statement of operations. Other Commitments or Contingencies Under the terms of each of the One Uptown joint venture agreements, the Company has provided cost overrun and completion guarantees, as well as customary environmental indemnities, in favor of the joint venture partner, for each of the One Uptown joint ventures. See Note 4, “Investment in Unconsolidated Real Estate Ventures” for further information. In connection with the Schuylkill Yards Project, the Company entered into a neighborhood engagement program and, as of December 31, 2022, had $6.6 million of future fixed contractual obligations. The Company also committed to fund additional contributions under the program. As of December 31, 2022, the Company estimates that these additional contributions, which are not fixed under the terms of agreement, will be $2.2 million. In connection with the formation of the Commerce Square Venture, the Company has committed to investing an additional $20.0 million of preferred equity in the properties on a pari passu basis with its joint venture partner of which $7.2 million has been contributed by the Company as of December 31, 2022. As part of the Company’s September 2004 acquisition of a portfolio of properties (which the Company refers to as the “TRC acquisition”), the Company acquired its interest in Two Logan Square, a 708,844 square foot office building in Philadelphia, Pennsylvania primarily through its ownership of a second and third mortgage secured by this property. This property is consolidated, as the borrower is a variable interest entity and the Company, through its ownership of the second and third mortgages, is the primary beneficiary. On October 21, 2020, the Company also acquired the $79.8 million first mortgage on the property from the third-party mortgage lender pursuant to an agreement with certain of the former owners. Under the agreement, the Company has agreed to not take title to Two Logan until the earlier of June 2026 or the occurrence of certain events related to the ownership interests of certain former owners. If the Company were to sell the restricted property before the expiration of the restricted period in a non-exempt transaction, the Company may be required to make significant payments to certain of the former owners of Two Logan Square on account of tax liabilities attributed to them. Additionally, the Company will be required to pay these certain former owners an amount estimated at approximately $0.6 million to redeem their residual interest in the fee owner of this property. The $0.6 million payment is included within “Other liabilities” on the consolidated balance sheets. The Company invests in its properties and regularly incurs capital expenditures in the ordinary course of business to maintain the properties. The Company believes that such expenditures enhance its competitiveness. The Company also enters into construction, utility and service contracts in the ordinary course of business which may extend beyond one year. These contracts typically provide for cancellation with insignificant or no cancellation penalties.