Equity Transactions	12 Months Ended
Dec. 31, 2018
Equity [Abstract]
Equity Transactions	Equity Transactions Preferred Securities Offerings In April 2016, the Company redeemed all of the issued and outstanding 2,950,000 shares of the Company's 7.125% Series H Cumulative Redeemable Preferred Stock ("Series H") for $25.00 per share for $73.8 million in cash. In connection with the Series H redemption, the Operating Partnership redeemed the Series H 7.125% Preferred Interest. The notice of redemption was given in March 2016, which resulted in the Company and the Operating Partnership each recording $2.5 million in excess of redemption value over carrying value charge to 2016 net income attributable to common stockholders and net income related to unitholders, respectively. Common Stock Offerings In September 2018, the Company entered into a new equity distribution agreement pursuant to which the Company may offer and sell shares of its common stock having an aggregate gross sales price of up to $900.0 million (the "2018 ATM Program"). In connection with the 2018 ATM Program, the Company may also enter into related forward sale agreements whereby, at the Company’s discretion, it may sell shares of its common stock under the 2018 ATM Program under forward sale agreements. The use of a forward sale agreement would allow the Company to lock in a share price on the sale of shares of its common stock at the time the agreement is executed, but defer receiving the proceeds from the sale of shares until a later date. The Company anticipates using the net proceeds, which are contributed to the Operating Partnership, to acquire, develop, or redevelop properties, which primarily will be apartment communities, to make other investments and for working capital or general corporate purposes, which may include the repayment of indebtedness. Upon entering into the 2018 ATM Program, the Company simultaneously terminated its existing equity distribution agreements, which were entered into in March 2016 in connection with its prior at-the-market equity offering program (the "2016 ATM Program"). During the year ended December 31, 2018, the Company did not sell any shares of its common stock through the 2018 ATM Program or through the 2016 ATM Program. Since commencement of the 2018 ATM Program, as of December 31, 2018, the Company has not sold any shares of its common stock and there are no outstanding forward sale agreements, and $900.0 million of shares remains available to be sold under this program. During 2017, the Company issued 345,444 shares of common stock, through the 2016 ATM program at an average price of $260.38 per share for total proceeds of $89.1 million, net of fees and commissions. For the year ended December 31, 2016, the Company did not issue any shares of common stock pursuant to the 2016 ATM Program. Operating Partnership Units and Long Term Incentive Plan ("LTIP") Units As of December 31, 2018 and 2017, the Operating Partnership had outstanding 2,171,309 and 2,054,814 operating partnership units and 134,080 and 213,300 vested LTIP units, respectively. The Operating Partnership’s general partner, Essex, owned 96.6% and 96.7% of the partnership interests in the Operating Partnership as of December 31, 2018 and 2017, respectively, and Essex is responsible for the management of the Operating Partnership’s business. As the general partner of the Operating Partnership, Essex effectively controls the ability to issue common stock of Essex upon a limited partner’s notice of redemption. Essex has generally acquired Operating Partnership limited partnership units ("OP Units") upon a limited partner’s notice of redemption in exchange for shares of its common stock. The redemption provisions of OP Units owned by limited partners that permit Essex to settle in either cash or common stock at the option of Essex were further evaluated in accordance with applicable accounting guidance to determine whether temporary or permanent equity classification on the balance sheet is appropriate. The Operating Partnership evaluated this guidance, including the requirement to settle in unregistered shares, and determined that, with few exceptions, these OP Units meet the requirements to qualify for presentation as permanent equity. LTIP units represent an interest in the Operating Partnership for services rendered or to be rendered by the LTIP unit holder in its capacity as a partner, or in anticipation of becoming a partner, in the Operating Partnership. Upon the occurrence of specified events, LTIP units may over time achieve full parity with common units of the Operating Partnership for all purposes. Upon achieving full parity, LTIP units will be exchanged for an equal number of the OP Units. The collective redemption value of OP Units and LTIP units owned by the limited partners, not including Essex, was approximately $565.3 million and $547.5 million based on the closing price of Essex's common stock as of December 31, 2018 and 2017, respectively.

Equity Transactions

Preferred Securities Offerings

In April 2016, the Company redeemed all of the issued and outstanding 2,950,000 shares of the Company's 7.125% Series H Cumulative Redeemable Preferred Stock ("Series H") for $25.00 per share for $73.8 million in cash. In connection with the Series H redemption, the Operating Partnership redeemed the Series H 7.125% Preferred Interest. The notice of redemption was given in March 2016, which resulted in the Company and the Operating Partnership each recording $2.5 million in excess of redemption value over carrying value charge to 2016 net income attributable to common stockholders and net income related to unitholders, respectively.

Common Stock Offerings

In September 2018, the Company entered into a new equity distribution agreement pursuant to which the Company may offer and sell shares of its common stock having an aggregate gross sales price of up to $900.0 million (the "2018 ATM Program"). In connection with the 2018 ATM Program, the Company may also enter into related forward sale agreements whereby, at the Company’s discretion, it may sell shares of its common stock under the 2018 ATM Program under forward sale agreements. The use of a forward sale agreement would allow the Company to lock in a share price on the sale of shares of its common stock at the time the agreement is executed, but defer receiving the proceeds from the sale of shares until a later date. The Company anticipates using the net proceeds, which are contributed to the Operating Partnership, to acquire, develop, or redevelop properties, which primarily will be apartment communities, to make other investments and for working capital or general corporate purposes, which may include the repayment of indebtedness.

Upon entering into the 2018 ATM Program, the Company simultaneously terminated its existing equity distribution agreements, which were entered into in March 2016 in connection with its prior at-the-market equity offering program (the "2016 ATM Program"). During the year ended December 31, 2018, the Company did not sell any shares of its common stock through the 2018 ATM Program or through the 2016 ATM Program. Since commencement of the 2018 ATM Program, as of December 31, 2018, the Company has not sold any shares of its common stock and there are no outstanding forward sale agreements, and $900.0 million of shares remains available to be sold under this program. During 2017, the Company issued 345,444 shares of common stock, through the 2016 ATM program at an average price of $260.38 per share for total proceeds of $89.1 million, net of fees and commissions. For the year ended December 31, 2016, the Company did not issue any shares of common stock pursuant to the 2016 ATM Program.

Operating Partnership Units and Long Term Incentive Plan ("LTIP") Units

As of December 31, 2018 and 2017, the Operating Partnership had outstanding 2,171,309 and 2,054,814 operating partnership units and 134,080 and 213,300 vested LTIP units, respectively. The Operating Partnership’s general partner, Essex, owned 96.6% and 96.7% of the partnership interests in the Operating Partnership as of December 31, 2018 and 2017, respectively, and Essex is responsible for the management of the Operating Partnership’s business. As the general partner of the Operating Partnership, Essex effectively controls the ability to issue common stock of Essex upon a limited partner’s notice of redemption. Essex has generally acquired Operating Partnership limited partnership units ("OP Units") upon a limited partner’s notice of redemption in exchange for shares of its common stock. The redemption provisions of OP Units owned by limited partners that permit Essex to settle in either cash or common stock at the option of Essex were further evaluated in accordance with applicable accounting guidance to determine whether temporary or permanent equity classification on the balance sheet is appropriate. The Operating Partnership evaluated this guidance, including the requirement to settle in unregistered shares, and determined that, with few exceptions, these OP Units meet the requirements to qualify for presentation as permanent equity.

LTIP units represent an interest in the Operating Partnership for services rendered or to be rendered by the LTIP unit holder in its capacity as a partner, or in anticipation of becoming a partner, in the Operating Partnership. Upon the occurrence of specified events, LTIP units may over time achieve full parity with common units of the Operating Partnership for all purposes. Upon achieving full parity, LTIP units will be exchanged for an equal number of the OP Units.

The collective redemption value of OP Units and LTIP units owned by the limited partners, not including Essex, was approximately $565.3 million and $547.5 million based on the closing price of Essex's common stock as of December 31, 2018 and 2017, respectively.