Commitments and Contingencies	12 Months Ended
Dec. 31, 2017
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	23. Commitments and Contingencies Insurance We carry commercial general liability coverage on our properties, with limits of liability customary within the industry. Similarly, we are insured against the risk of direct and indirect physical damage to our properties including coverage for the perils such as floods, earthquakes and windstorms. Our policies also cover the loss of rental income during an estimated reconstruction period. Our policies reflect limits and deductibles customary in the industry and specific to the buildings and portfolio. We also obtain title insurance policies when acquiring new properties. We currently have coverage for losses incurred in connection with both domestic and foreign terrorist-related activities. While we do carry commercial general liability insurance, property insurance and terrorism insurance with respect to our properties, these policies include limits and terms we consider commercially reasonable. In addition, there are certain losses (including, but not limited to, losses arising from known environmental conditions or acts of war) that are not insured, in full or in part, because they are either uninsurable or the cost of insurance makes it, in our belief, economically impractical to maintain such coverage. Should an uninsured loss arise against us, we would be required to use our own funds to resolve the issue, including litigation costs. We believe the policy specifications and insured limits are adequate given the relative risk of loss, the cost of the coverage and industry practice and, in consultation with our insurance advisors, we believe the properties in our portfolio are adequately insured. Other Commitments and Contingencies We are a party to various claims and routine litigation arising in the ordinary course of business. Some of these claims or others to which we may be subject from time to time, including claims arising specifically from the Formation Transactions, in connection with our initial public offering, may result in defense costs, settlements, fines or judgments against us, some of which are not, or cannot be, covered by insurance. Payment of any such costs, settlements, fines or judgments that are not insured could have an adverse impact on our financial position and results of operations. Should any litigation arise in connection with the Formation Transactions, we would contest it vigorously. In addition, certain litigation or the resolution of certain litigation may affect the availability or cost of some of our insurance coverage, which could adversely impact our results of operations and cash flow, expose us to increased risks that would be uninsured, and/or adversely impact our ability to attract officers and directors. The terms of our mortgage debt and certain side letters in place include certain restrictions and covenants which may limit, among other things, certain investments, the incurrence of additional indebtedness and liens and the disposition or other transfer of assets and interests in the borrower and other credit parties, and require compliance with certain debt yield, debt service coverage and loan to value ratios. In addition, our revolving credit facility contains representations, warranties, covenants, other agreements and events of default customary for agreements of this type with comparable companies. As of December 31, 2017, we believe we are in compliance with all of our covenants. 718 Fifth Avenue - Put Right Prior to the Formation Transactions, an affiliate of our Predecessor owned a 25.0% interest in 718 Fifth Avenue, a five-story building containing 19,050 square feet of prime retail space that is located on the southwest corner of 56th Street and Fifth Avenue in New York, (based on its 50.0% interest in a joint venture that held a 50.0% tenancy-in-common interest in the property). Prior to the completion of the Formation Transactions, this interest was sold to its partner in the 718 Fifth Avenue joint venture, who is also our joint venture partner in 712 Fifth Avenue, New York, New York. In connection with this sale, we granted our joint venture partner a put right, pursuant to which the 712 Fifth Avenue joint venture would be required to purchase the entire direct or indirect interests then held by our joint venture partner or its affiliates in 718 Fifth Avenue at a purchase price equal to the fair market value of such interests. The put right may be exercised at any time after September 10, 2018 with 12 months written notice and the actual purchase occurring no earlier than September 10, 2019. If the put right is exercised and the 712 Fifth Avenue joint venture acquires the 50.0% tenancy-in-common interest in the property by our joint venture partner, we will own a 25.0% interest in 718 Fifth Avenue based on current ownership interests.

23. Commitments and Contingencies

Insurance

We carry commercial general liability coverage on our properties, with limits of liability customary within the industry. Similarly, we are insured against the risk of direct and indirect physical damage to our properties including coverage for the perils such as floods, earthquakes and windstorms. Our policies also cover the loss of rental income during an estimated reconstruction period. Our policies reflect limits and deductibles customary in the industry and specific to the buildings and portfolio. We also obtain title insurance policies when acquiring new properties. We currently have coverage for losses incurred in connection with both domestic and foreign terrorist-related activities. While we do carry commercial general liability insurance, property insurance and terrorism insurance with respect to our properties, these policies include limits and terms we consider commercially reasonable. In addition, there are certain losses (including, but not limited to, losses arising from known environmental conditions or acts of war) that are not insured, in full or in part, because they are either uninsurable or the cost of insurance makes it, in our belief, economically impractical to maintain such coverage. Should an uninsured loss arise against us, we would be required to use our own funds to resolve the issue, including litigation costs. We believe the policy specifications and insured limits are adequate given the relative risk of loss, the cost of the coverage and industry practice and, in consultation with our insurance advisors, we believe the properties in our portfolio are adequately insured.

Other Commitments and Contingencies

We are a party to various claims and routine litigation arising in the ordinary course of business. Some of these claims or others to which we may be subject from time to time, including claims arising specifically from the Formation Transactions, in connection with our initial public offering, may result in defense costs, settlements, fines or judgments against us, some of which are not, or cannot be, covered by insurance. Payment of any such costs, settlements, fines or judgments that are not insured could have an adverse impact on our financial position and results of operations. Should any litigation arise in connection with the Formation Transactions, we would contest it vigorously. In addition, certain litigation or the resolution of certain litigation may affect the availability or cost of some of our insurance coverage, which could adversely impact our results of operations and cash flow, expose us to increased risks that would be uninsured, and/or adversely impact our ability to attract officers and directors.

The terms of our mortgage debt and certain side letters in place include certain restrictions and covenants which may limit, among other things, certain investments, the incurrence of additional indebtedness and liens and the disposition or other transfer of assets and interests in the borrower and other credit parties, and require compliance with certain debt yield, debt service coverage and loan to value ratios. In addition, our revolving credit facility contains representations, warranties, covenants, other agreements and events of default customary for agreements of this type with comparable companies. As of December 31, 2017, we believe we are in compliance with all of our covenants.

718 Fifth Avenue - Put Right

Prior to the Formation Transactions, an affiliate of our Predecessor owned a 25.0% interest in 718 Fifth Avenue, a five-story building containing 19,050 square feet of prime retail space that is located on the southwest corner of 56th Street and Fifth Avenue in New York, (based on its 50.0% interest in a joint venture that held a 50.0% tenancy-in-common interest in the property). Prior to the completion of the Formation Transactions, this interest was sold to its partner in the 718 Fifth Avenue joint venture, who is also our joint venture partner in 712 Fifth Avenue, New York, New York. In connection with this sale, we granted our joint venture partner a put right, pursuant to which the 712 Fifth Avenue joint venture would be required to purchase the entire direct or indirect interests then held by our joint venture partner or its affiliates in 718 Fifth Avenue at a purchase price equal to the fair market value of such interests. The put right may be exercised at any time after September 10, 2018 with 12 months written notice and the actual purchase occurring no earlier than September 10, 2019. If the put right is exercised and the 712 Fifth Avenue joint venture acquires the 50.0% tenancy-in-common interest in the property by our joint venture partner, we will own a 25.0% interest in 718 Fifth Avenue based on current ownership interests.