Significant Transactions During the Nine Months Ended 2017 and Subsequent Events	9 Months Ended
Sep. 30, 2017
Business Combinations [Abstract]
Significant Transactions During the Nine Months Ended 2017 and Subsequent Events	Significant Transactions During The Nine Months Ended 2017 and Subsequent Events Significant Transactions Acquisitions In January 2017, the Company purchased its joint venture partner's 50.0% interest in Palm Valley, for a contract price of $183.0 million. Prior to the purchase, an approximately $220.0 million mortgage encumbered the property. Concurrent with the closing of the acquisition, the entire mortgage balance was repaid and the property is now unencumbered. Palm Valley has 1,098 apartment homes, within four communities, and is located in San Jose, CA. As a result of this acquisition, the Company realized a gain on remeasurement of co-investment of $88.6 million upon consolidation. In March 2017, the Company converted its existing $15.3 million preferred equity investment in Sage at Cupertino, a 230 apartment home community located in San Jose, CA, into a 40.5% common equity ownership interest in the property. The Company issued DownREIT units to the other members, including an affiliate of the Marcus & Millichap Company, based on an estimated property valuation of $90.0 million. See Note 5, Related Party Transactions, for additional details. At the time of acquisition, the property was encumbered by a $52.0 million bridge loan from the Company. The Company consolidates the property based on a VIE analysis performed by the Company. The consolidated fair value of acquired communities listed in the preceding paragraphs above were included on the Company's condensed consolidated balance sheet as follows: $169.5 million was included in land and land improvements, $365.7 million was included in buildings and improvements, and $3.2 million was included in prepaid expenses and other assets. In August 2017, a Company co-investment, Wesco V, LLC ("Wesco V") acquired 8th & Republican, a 211 apartment home community located in Seattle, WA, for a total contract price of $101.3 million. The property is encumbered by a $55.0 million related party bridge loan from the Company, which accrues interest at 3.5% and is scheduled to mature on December 16, 2017. See the "Co-Investments" section below for further details related to the creation of Wesco V. See Note 5, Related Party Transactions, for additional details related to the related party bridge loan. Also in August 2017, Wesco V acquired 360 Residences, a 213 apartment home community, located in San Jose, CA, for a total contract price of $133.5 million. In connection with this acquisition, Wesco V assumed $57.9 million of mortgage debt, with an effective interest rate of 3.4% and a maturity date of May 2022. Dispositions In January 2017, the Company sold Jefferson at Hollywood, a 270 apartment home community located in Los Angeles, CA, for $132.5 million, resulting in a gain of $26.2 million. In August 2017, a Company co-investment, Wesco I, LLC ("Wesco I") sold Madrid, a 230 apartment home community located in Mission Viejo, CA, for $83.0 million, which resulted in a gain of $10.1 million for the Company, recorded in the statement of income as equity income in co-investments. Wesco I used $30.1 million of proceeds to repay the loan on the property. Preferred Equity Investments During the nine months ended September 30, 2017, the Company made commitments to fund $89.3 million in five preferred equity investments, located in Irvine, CA, Seattle, WA, Marina del Rey, CA, Woodland Hills, CA, and San Jose, CA. These investments have initial accrued preferred returns ranging from 9.5%-11.0%, with maturities ranging from March 2020 to August 2024. As of September 30, 2017, the Company has funded $38.0 million of the $89.3 million commitment. In April 2017, the Company received cash of $12.6 million from the partial redemption of a preferred equity investment in a joint venture that holds a property located in Seattle, WA. The Company recorded a reduction of $12.4 million in its preferred equity investment. The Company recognized a gain of $0.3 million as a result of this early redemption, which is included in equity income from co-investments in the condensed consolidated statement of income and comprehensive income. In August 2017, the Company received cash of $11.7 million for a full redemption of a preferred equity investment class and $6.9 million for a partial redemption of another preferred equity investment class in a joint venture that holds a property in San Jose, CA. The Company's remaining preferred equity investment in this joint venture was $13.4 million as of September 30, 2017. Notes Receivable In May 2017, the Company made a commitment to fund a mezzanine loan of $13.2 million to a limited liability company that owns a development project located in Anaheim, CA. The investment will initially accrue interest based on a 10.0% compounded return. This investment is scheduled to mature in May 2021. As of September 30, 2017, the Company had fully funded the $13.2 million commitment. Co-investments In August 2017, the Company formed a new joint venture entity, Wesco V, with an institutional partner. Each partner has a 50.0% ownership interest and an initial equity commitment of $150.0 million. The joint venture is unconsolidated for financial reporting purposes. Senior Unsecured Debt In March 2017, the Company paid off $300.0 million of 5.500% senior unsecured notes. In April 2017, the Company issued $350.0 million of 10-year 3.625% senior unsecured notes. The interest is paid semi-annually in arrears on May 1 and November 1 of each year commencing on November 1, 2017 until the maturity date of May 1, 2027. The Company used the net proceeds of this offering to repay indebtedness under its unsecured lines of credit and for other general corporate and working capital purposes. Private Placement Bond Redemption In July 2017, the Company repaid $40.0 million in private placement bonds with a coupon rate of 4.5% and a stated maturity date of September 2017. This represented the total outstanding balance of these unsecured bonds. Common Stock During the nine months ended September 30, 2017, the Company issued 311,873 shares of common stock, through our equity distribution program at an average price of $260.30 per share for proceeds of $80.4 million, net of fees and commissions. There were no such sales during the three months ended September 30, 2017. Subsequent to quarter end through October 30, 2017, the Company issued 33,571 additional shares of common stock through its equity distribution program at an average price of $261.19 per share for proceeds of $8.7 million, net of fees and commissions. Subsequent Events In October 2017, the Company entered into an amendment to the Wesco I operating agreement to extend the joint venture. Under the amendment, the Company received an additional ownership interest in exchange for promote interest earned which is expected to be approximately $38.0 million. As a result of the amendment, the Company's ownership interest in Wesco I increased to approximately 58.0%. In October 2017, the Company made a commitment to fund a $40.0 million preferred equity investment in a multifamily development project located in Los Angeles, CA with an accrued initial preferred return of 11.3% and an October 2021 maturity date.

Significant Transactions During The Nine Months Ended 2017 and Subsequent Events

Significant Transactions

Acquisitions

In January 2017, the Company purchased its joint venture partner's 50.0% interest in Palm Valley, for a contract price of $183.0 million. Prior to the purchase, an approximately $220.0 million mortgage encumbered the property. Concurrent with the closing of the acquisition, the entire mortgage balance was repaid and the property is now unencumbered. Palm Valley has 1,098 apartment homes, within four communities, and is located in San Jose, CA. As a result of this acquisition, the Company realized a gain on remeasurement of co-investment of $88.6 million upon consolidation.

In March 2017, the Company converted its existing $15.3 million preferred equity investment in Sage at Cupertino, a 230 apartment home community located in San Jose, CA, into a 40.5% common equity ownership interest in the property. The Company issued DownREIT units to the other members, including an affiliate of the Marcus & Millichap Company, based on an estimated property valuation of $90.0 million. See Note 5, Related Party Transactions, for additional details. At the time of acquisition, the property was encumbered by a $52.0 million bridge loan from the Company. The Company consolidates the property based on a VIE analysis performed by the Company.

The consolidated fair value of acquired communities listed in the preceding paragraphs above were included on the Company's condensed consolidated balance sheet as follows: $169.5 million was included in land and land improvements, $365.7 million was included in buildings and improvements, and $3.2 million was included in prepaid expenses and other assets.

In August 2017, a Company co-investment, Wesco V, LLC ("Wesco V") acquired 8th & Republican, a 211 apartment home community located in Seattle, WA, for a total contract price of $101.3 million. The property is encumbered by a $55.0 million related party bridge loan from the Company, which accrues interest at 3.5% and is scheduled to mature on December 16, 2017. See the "Co-Investments" section below for further details related to the creation of Wesco V. See Note 5, Related Party Transactions, for additional details related to the related party bridge loan.

Also in August 2017, Wesco V acquired 360 Residences, a 213 apartment home community, located in San Jose, CA, for a total contract price of $133.5 million. In connection with this acquisition, Wesco V assumed $57.9 million of mortgage debt, with an effective interest rate of 3.4% and a maturity date of May 2022.

Dispositions

In January 2017, the Company sold Jefferson at Hollywood, a 270 apartment home community located in Los Angeles, CA, for $132.5 million, resulting in a gain of $26.2 million.

In August 2017, a Company co-investment, Wesco I, LLC ("Wesco I") sold Madrid, a 230 apartment home community located in Mission Viejo, CA, for $83.0 million, which resulted in a gain of $10.1 million for the Company, recorded in the statement of income as equity income in co-investments. Wesco I used $30.1 million of proceeds to repay the loan on the property.

Preferred Equity Investments

During the nine months ended September 30, 2017, the Company made commitments to fund $89.3 million in five preferred equity investments, located in Irvine, CA, Seattle, WA, Marina del Rey, CA, Woodland Hills, CA, and San Jose, CA. These investments have initial accrued preferred returns ranging from 9.5%-11.0%, with maturities ranging from March 2020 to August 2024. As of September 30, 2017, the Company has funded $38.0 million of the $89.3 million commitment.

In April 2017, the Company received cash of $12.6 million from the partial redemption of a preferred equity investment in a joint venture that holds a property located in Seattle, WA. The Company recorded a reduction of $12.4 million in its preferred equity investment. The Company recognized a gain of $0.3 million as a result of this early redemption, which is included in equity income from co-investments in the condensed consolidated statement of income and comprehensive income.

In August 2017, the Company received cash of $11.7 million for a full redemption of a preferred equity investment class and $6.9 million for a partial redemption of another preferred equity investment class in a joint venture that holds a property in San Jose, CA. The Company's remaining preferred equity investment in this joint venture was $13.4 million as of September 30, 2017.

Notes Receivable

In May 2017, the Company made a commitment to fund a mezzanine loan of $13.2 million to a limited liability company that owns a development project located in Anaheim, CA. The investment will initially accrue interest based on a 10.0% compounded return. This investment is scheduled to mature in May 2021. As of September 30, 2017, the Company had fully funded the $13.2 million commitment.

Co-investments

In August 2017, the Company formed a new joint venture entity, Wesco V, with an institutional partner. Each partner has a 50.0% ownership interest and an initial equity commitment of $150.0 million. The joint venture is unconsolidated for financial reporting purposes.

Senior Unsecured Debt

In March 2017, the Company paid off $300.0 million of 5.500% senior unsecured notes.

In April 2017, the Company issued $350.0 million of 10-year 3.625% senior unsecured notes. The interest is paid semi-annually in arrears on May 1 and November 1 of each year commencing on November 1, 2017 until the maturity date of May 1, 2027. The Company used the net proceeds of this offering to repay indebtedness under its unsecured lines of credit and for other general corporate and working capital purposes.

Private Placement Bond Redemption

In July 2017, the Company repaid $40.0 million in private placement bonds with a coupon rate of 4.5% and a stated maturity date of September 2017. This represented the total outstanding balance of these unsecured bonds.

Common Stock

During the nine months ended September 30, 2017, the Company issued 311,873 shares of common stock, through our equity distribution program at an average price of $260.30 per share for proceeds of $80.4 million, net of fees and commissions. There were no such sales during the three months ended September 30, 2017.

Subsequent to quarter end through October 30, 2017, the Company issued 33,571 additional shares of common stock through its equity distribution program at an average price of $261.19 per share for proceeds of $8.7 million, net of fees and commissions.

Subsequent Events

In October 2017, the Company entered into an amendment to the Wesco I operating agreement to extend the joint venture. Under the amendment, the Company received an additional ownership interest in exchange for promote interest earned which is expected to be approximately $38.0 million. As a result of the amendment, the Company's ownership interest in Wesco I increased to approximately 58.0%.

In October 2017, the Company made a commitment to fund a $40.0 million preferred equity investment in a multifamily development project located in Los Angeles, CA with an accrued initial preferred return of 11.3% and an October 2021 maturity date.