Significant Transactions During the First Quarter of 2013 and Subsequent Events	3 Months Ended
Mar. 31, 2013
Significant Transactions During the First Quarter of 2013 and Subsequent Events [Abstract]
Significant Transactions During the First Quarter of 2013 and Subsequent Events	(2) Significant Transactions During the First Quarter of 2013 and Subsequent Events Acquisitions In January 2013, the Company acquired Annaliese, a 56 unit community located in Seattle, Washington for $19.0 million. The property was built in 2009 and is located in the South Lake Union submarket. In February 2013, the Company purchased Fox Plaza, a 444 unit property located in San Francisco, California, for $135.0 million. Built in 1968, the property is a 29 story high rise tower with Fox Plaza apartments located on floors 14 through 29. The purchase price did not include floors 1 through 12 of commercial office space but did include an adjacent two story building comprised of approximately 37,800 square feet of space leased to retail and office tenants and a two story underground parking garage comprised of 405 stalls. Common Stock During the first quarter, the Company sold 817,445 shares of common stock for $122.9 million, net of commissions, at an average per share price of $151.82. Subsequent to quarter end, the Company has not sold any shares of common stock. Unsecured Bond Offering In April 2013, the Company issued $300 million aggregate principal amount of its 3.25% Senior Notes due on May 1, 2023 (the "Notes"). The net proceeds from the issuance of Notes were approximately $295.2 million, after deducting the underwriters' discounts and estimated offering expenses. Dispositions In January, the Company sold the land parcel held for future development located in Palo Alto, California for $9.1 million, resulting in a gain of $1.5 million.

(2) Significant Transactions During the First Quarter of 2013 and Subsequent Events

Acquisitions

In January 2013, the Company acquired Annaliese, a 56 unit community located in Seattle, Washington for $19.0 million. The property was built in 2009 and is located in the South Lake Union submarket.

In February 2013, the Company purchased Fox Plaza, a 444 unit property located in San Francisco, California, for $135.0 million. Built in 1968, the property is a 29 story high rise tower with Fox Plaza apartments located on floors 14 through 29. The purchase price did not include floors 1 through 12 of commercial office space but did include an adjacent two story building comprised of approximately 37,800 square feet of space leased to retail and office tenants and a two story underground parking garage comprised of 405 stalls.

Common Stock

During the first quarter, the Company sold 817,445 shares of common stock for $122.9 million, net of commissions, at an average per share price of $151.82. Subsequent to quarter end, the Company has not sold any shares of common stock.

Unsecured Bond Offering

In April 2013, the Company issued $300 million aggregate principal amount of its 3.25% Senior Notes due on May 1, 2023 (the "Notes"). The net proceeds from the issuance of Notes were approximately $295.2 million, after deducting the underwriters' discounts and estimated offering expenses.

Dispositions

In January, the Company sold the land parcel held for future development located in Palo Alto, California for $9.1 million, resulting in a gain of $1.5 million.