Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	20. Commitments and Contingencies Insurance We maintain general liability insurance with limits of $300,000,000 per occurrence and per property, and all risk property and rental value insurance with limits of $2.0 billion per occurrence, with sub-limits for certain perils such as flood and earthquake. Our California properties have earthquake insurance with coverage of $180,000,000 per occurrence and in the annual aggregate, subject to a deductible in the amount of 5% of the value of the affected property. We maintain coverage for terrorism acts with limits of $4.0 billion per occurrence and in the aggregate, and $2.0 billion per occurrence and in the aggregate for terrorism involving nuclear, biological, chemical and radiological (“NBCR”) terrorism events, as defined by Terrorism Risk Insurance Program Reauthorization Act of 2015, which expires in December 2020. Penn Plaza Insurance Company, LLC (“PPIC”), our wholly owned consolidated subsidiary, acts as a re-insurer with respect to a portion of all risk property and rental value insurance and a portion of our earthquake insurance coverage, and as a direct insurer for coverage for acts of terrorism including NBCR acts. Coverage for acts of terrorism (excluding NBCR acts) is fully reinsured by third party insurance companies and the Federal government with no exposure to PPIC. For NBCR acts, PPIC is responsible for a deductible of $1,622,000 ($1,976,000 for 2017) and 16% (17% for 2017) of the balance of a covered loss and the Federal government is responsible for the remaining portion of a covered loss. We are ultimately responsible for any loss incurred by PPIC. We continue to monitor the state of the insurance market and the scope and costs of coverage for acts of terrorism. However, we cannot anticipate what coverage will be available on commercially reasonable terms in the future. Our debt instruments, consisting of mortgage loans secured by our properties which are non-recourse to us, senior unsecured notes and revolving credit agreements contain customary covenants requiring us to maintain insurance. Although we believe that we have adequate insurance coverage for purposes of these agreements, we may not be able to obtain an equivalent amount of coverage at reasonable costs in the future. Further, if lenders insist on greater coverage than we are able to obtain it could adversely affect our ability to finance our properties and expand our portfolio. Other Commitments and Contingencies We are from time to time involved in legal actions arising in the ordinary course of business. In our opinion, after consultation with legal counsel, the outcome of such matters is not expected to have a material adverse effect on our financial position, results of operations or cash flows. Each of our properties has been subjected to varying degrees of environmental assessment at various times. The environmental assessments did not reveal any material environmental contamination. However, there can be no assurance that the identification of new areas of contamination, changes in the extent or known scope of contamination, the discovery of additional sites, or changes in cleanup requirements would not result in significant costs to us. Our mortgage loans are non-recourse to us. However, in certain cases we have provided guarantees or master leased tenant space. These guarantees and master leases terminate either upon the satisfaction of specified circumstances or repayment of the underlying loans. As of December 31, 2016, the aggregate dollar amount of these guarantees and master leases is approximately $737,000,000. As of December 31, 2016, $19,847,000 of letters of credit was outstanding under one of our unsecured revolving credit facilities. Our unsecured revolving credit facilities contain financial covenants that require us to maintain minimum interest coverage and maximum debt to market capitalization ratios, and provide for higher interest rates in the event of a decline in our ratings below Baa3/BBB. Our unsecured revolving credit facilities also contain customary conditions precedent to borrowing, including representations and warranties, and also contain customary events of default that could give rise to accelerated repayment, including such items as failure to pay interest or principal. As of December 31, 2016, we expect to fund additional capital to certain of our partially owned entities aggregating approximately $173,000,000, which includes our share of the commitments of the Farley Post Office redevelopment joint venture. As of December 31, 2016, we have construction commitments aggregating $653,940,000.