Subsequent Event	12 Months Ended
Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Stock-based Compensation On January 12, 2018, the Compensation Committee approved the issuance of appreciation-only long-term incentive plan units, or “AO LTIP Units”, pursuant to the Plan to certain of our officers and employees. In connection with the approval of AO LTIP Units, Vornado, in its capacity as sole general partner of the Operating Partnership, amended the Second Amended and Restated Agreement of Limited Partnership of the Operating Partnership (the “Partnership Agreement”) in order to establish the terms of the new class of partnership interests known as AO LTIP Units. AO LTIP Units are a class of partnership interests in the Operating Partnership that are intended to qualify as “profits interests” for federal income tax purposes and generally only allow the recipient to realize value to the extent the fair market value of a Vornado common share exceeds the threshold level set at the time the AO LTIP Units are granted, subject to any vesting conditions applicable to the award. The threshold level is intended to be equal to 100% of the then fair market value of a Vornado common share on the date of grant. The value of vested AO LTIP Units is realized through conversion of the AO LTIP Units into Class A Operating Partnership units. The number of Class A Units into which vested AO LTIP Units may be converted is determined based on the quotient of (i) the excess of the conversion value on the conversion date over the threshold value designated at the time the AO LTIP Unit was granted, divided by (ii) the conversion value on the conversion date. The “conversion value” is the value of a Vornado common share on the conversion date multiplied by the Conversion Factor as defined in the Partnership Agreement, which is currently one. AO LTIP Units have a term of ten years from the grant date. Each holder will generally receive special income allocations in respect of an AO LTIP Unit equal to 10% (or such other percentage specified in the applicable award agreement) of the income allocated in respect of a Class A Unit. Upon conversion of AO LTIP Units to Class A Units, holders will be entitled to receive in respect of each such AO LTIP Unit, on a per unit basis, a special distribution equal to 10% (or such other percentage specified in the applicable award agreement) of the distributions received by a holder of an equivalent number of Class A Units during the period from the grant date of the AO LTIP Units through the date of conversion. Other On January 4 and 11, 2018, we redeemed all of the outstanding 6.625% Series G and 6.625% Series I cumulative redeemable preferred shares/units at their redemption price of $25.00 per share/unit, or $470,000,000 in the aggregate, plus accrued and unpaid dividends/distributions through the date of redemption (see Note 10 - Shareholder’s Equity/Partners’ Capital). On January 5, 2018, we completed a $100,000,000 refinancing of 33-00 Northern Boulevard (Center Building), a 471,000 square foot office building in Long Island City, New York. The seven-year loan is at LIBOR plus 1.80%, which was swapped to a fixed rate of 4.14%. The loan is interest only for the first five years and includes principal amortization of $1,800,000 per annum beginning in year six. We realized net proceeds of approximately $37,200,000 after repayment of the existing 4.43% $59,800,000 mortgage and closing costs. On January 17, 2018, the Fund completed the sale of 11 East 68th Street, a property located on Madison Avenue and 68th Street, for $82,000,000. From the inception of this investment through its disposition, the Fund realized a $46,259,000 net gain.

Subsequent Event

Stock-based Compensation

On January 12, 2018, the Compensation Committee approved the issuance of appreciation-only long-term incentive plan units, or “AO LTIP Units”, pursuant to the Plan to certain of our officers and employees. In connection with the approval of AO LTIP Units, Vornado, in its capacity as sole general partner of the Operating Partnership, amended the Second Amended and Restated Agreement of Limited Partnership of the Operating Partnership (the “Partnership Agreement”) in order to establish the terms of the new class of partnership interests known as AO LTIP Units.

AO LTIP Units are a class of partnership interests in the Operating Partnership that are intended to qualify as “profits interests” for federal income tax purposes and generally only allow the recipient to realize value to the extent the fair market value of a Vornado common share exceeds the threshold level set at the time the AO LTIP Units are granted, subject to any vesting conditions applicable to the award. The threshold level is intended to be equal to 100% of the then fair market value of a Vornado common share on the date of grant. The value of vested AO LTIP Units is realized through conversion of the AO LTIP Units into Class A Operating Partnership units. The number of Class A Units into which vested AO LTIP Units may be converted is determined based on the quotient of (i) the excess of the conversion value on the conversion date over the threshold value designated at the time the AO LTIP Unit was granted, divided by (ii) the conversion value on the conversion date. The “conversion value” is the value of a Vornado common share on the conversion date multiplied by the Conversion Factor as defined in the Partnership Agreement, which is currently one. AO LTIP Units have a term of ten years from the grant date.

Each holder will generally receive special income allocations in respect of an AO LTIP Unit equal to 10% (or such other percentage specified in the applicable award agreement) of the income allocated in respect of a Class A Unit. Upon conversion of AO LTIP Units to Class A Units, holders will be entitled to receive in respect of each such AO LTIP Unit, on a per unit basis, a special distribution equal to 10% (or such other percentage specified in the applicable award agreement) of the distributions received by a holder of an equivalent number of Class A Units during the period from the grant date of the AO LTIP Units through the date of conversion.

Other

On January 4 and 11, 2018, we redeemed all of the outstanding 6.625% Series G and 6.625% Series I cumulative redeemable preferred shares/units at their redemption price of $25.00 per share/unit, or $470,000,000 in the aggregate, plus accrued and unpaid dividends/distributions through the date of redemption (see Note 10 - Shareholder’s Equity/Partners’ Capital).

On January 5, 2018, we completed a $100,000,000 refinancing of 33-00 Northern Boulevard (Center Building), a 471,000 square foot office building in Long Island City, New York. The seven-year loan is at LIBOR plus 1.80%, which was swapped to a fixed rate of 4.14%. The loan is interest only for the first five years and includes principal amortization of $1,800,000 per annum beginning in year six. We realized net proceeds of approximately $37,200,000 after repayment of the existing 4.43% $59,800,000 mortgage and closing costs.

On January 17, 2018, the Fund completed the sale of 11 East 68th Street, a property located on Madison Avenue and 68th Street, for $82,000,000. From the inception of this investment through its disposition, the Fund realized a $46,259,000 net gain.