WARRANTS	12 Months Ended
WARRANTS	Dec. 31, 2019
Warrants and Rights Note Disclosure [Abstract]
WARRANTS	WARRANTS On November 9, 2010, the Company entered into warrant agreements with certain funds of Pershing Square Capital Management, L.P. (“Pershing Square”) to purchase 1,916,667 shares of common stock at an exercise price of $50.00 per share (the “Sponsor Warrants”). Pershing Square exercised its Sponsor Warrants on June 30, 2017, resulting in a net issuance of 1,136,517 shares in accordance with the warrant provisions. In November 2010 and February 2011, HHC entered into certain warrant agreements (the “Management Warrants”) with David R. Weinreb, the Chief Executive Officer, Grant Herlitz, the President, and Andrew C. Richardson, the former Chief Financial Officer, in each case prior to his appointment to such position, to purchase 2,367,985, 315,731 and 178,971 shares, respectively, of common stock. The Management Warrants were granted at fair value in exchange for a combined total of approximately $19.0 million in cash from such executives at the commencement of their respective employment. Mr. Weinreb and Mr. Herlitz’s warrants had an exercise price of $42.23 per share, and Mr. Richardson’s warrants had an exercise price of $54.50 per share. Mr. Herlitz exercised his Management Warrants in early January 2017, resulting in the net issuance of 198,184 shares in accordance with the warrant provisions. Mr. Herlitz also donated 6,850 shares to a charitable trust, which were net share settled for 4,400 shares in accordance with the warrant provisions. In February, March and June 2017, Mr. Richardson exercised his Management Warrants, resulting in the net issuance of 98,549 shares in accordance with the warrant provisions. In June 2017, Mr. Weinreb exercised his Management Warrants, resulting in the net issuance of 1,614,803 shares in accordance with the warrant provisions. As of December 31, 2017, all Sponsor Warrants and Management Warrants have been exercised. The fair values for the Sponsor Warrants and Management Warrants as of December 31, 2016 were recorded as liabilities in the Consolidated Balance Sheets because the holders of these warrants could require the Company to settle such warrants in cash upon a change of control. The estimated fair values for the outstanding Sponsor Warrants and Management Warrants totaled $332.2 million as of December 31, 2016. The fair values were estimated using an option pricing model and Level 3 inputs due to the unavailability of comparable market data, as further discussed in Note 8 - Fair Value. Decreases and increases in the fair value of the Sponsor Warrants and Management Warrants prior to their settlements in 2017 were recognized as warrant liability gains or losses in the Consolidated Statements of Operations in the years ended December 31, 2017 and 2016. On October 7, 2016, the Company entered into a warrant agreement with its Chief Financial Officer, David R. O’Reilly, (the “O’Reilly Warrant”) prior to his appointment to the position. Upon exercise of his warrant, Mr. O’Reilly may acquire 50,125 shares of common stock at an exercise price of $112.08 per share. The O’Reilly Warrant was issued at fair value in exchange for a $1.0 million payment in cash from Mr. O’Reilly. The O’Reilly Warrant becomes exercisable on April 6, 2022, subject to earlier exercise upon certain change in control, separation and termination provisions. On June 16, 2017 and October 4, 2017, the Company entered into warrant agreements with its Chief Executive Officer, David R. Weinreb, (the “Weinreb Warrant”) and President, Grant Herlitz, (the “Herlitz Warrant”) to acquire 1,965,409 shares and 87,951 shares of common stock for the purchase price of $50.0 million and $2.0 million, respectively. The Weinreb Warrant would have become exercisable on June 15, 2022, at an exercise price of $124.64 per share, and the Herlitz Warrant would have become exercisable on October 3, 2022, at an exercise price of $117.01 per share, subject in each case to earlier exercise upon certain change in control, separation and termination provisions (but such warrants became exercisable in connection with Mr. Weinreb’s and Mr. Herlitz’s terminations of employment, as described below). The purchase prices paid by the respective executives for the O’Reilly Warrant, the Weinreb Warrant and the Herlitz Warrant, which qualify as equity instruments, are included within Additional paid-in capital in the Consolidated Balance Sheets at December 31, 2019 and 2018. On October 21, 2019, Mr. Weinreb and Mr. Herlitz stepped down from their roles as Chief Executive Officer and President of the Company, respectively. The Company and each of Mr. Weinreb and Mr. Herlitz have agreed to treat their terminations of employment as terminations without “cause” under their respective employment and warrant agreements with the Company. Thus, effective October 21, 2019, the Weinreb Warrant and Herlitz Warrant became exercisable by the terms of their respective warrant agreements in connection with their respective terminations of employment.

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.