v2.4.0.8

Stockholders' Equity (Details) (USD $) | 0 Months Ended | 6 Months Ended |  |  |  | 6 Months Ended | 0 Months Ended | 60 Months Ended |  |  |  |  | 6 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 30, 2013 | Mar. 27, 2013 | Jan. 29, 2013 | Jun. 30, 2013 | Jun. 18, 2013 | Dec. 31, 2012 | Jun. 30, 2013 Atm Program [Member] | Jun. 30, 2013 Issued in conjunction with debt exchange for 3.75% exchangeable senior notes [Member] | Jun. 30, 2013 Quarter 4 2012 [Member] | Jun. 30, 2013 Quarter 1 2013 [Member] | Jun. 30, 2013 Quarter 2 2013 [Member] | May 15, 2013 Series B Cumulative Redeemable Preferred Stock [Member] | Mar. 26, 2018 Series B Cumulative Redeemable Preferred Stock [Member] | Mar. 27, 2018 Series B Cumulative Redeemable Preferred Stock [Member] | Jun. 30, 2013 Series B Cumulative Redeemable Preferred Stock [Member] | Jun. 18, 2013 Series B Cumulative Redeemable Preferred Stock [Member] | Dec. 31, 2012 Series B Cumulative Redeemable Preferred Stock [Member] | Jun. 30, 2013 Series B Cumulative Redeemable Preferred Stock [Member] Quarter 2 2013 [Member] | Jun. 30, 2013 Series B Cumulative Redeemable Preferred Stock [Member] Quarter 3 2013 [Member] | Mar. 27, 2018 Depository shares of Series B Cumulative Redeemable Preferred [Member] | Jun. 30, 2013 Depository shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock, shares outstanding |  |  |  | 152,384,740 |  | 151,601,209 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
At the market stock offering program, aggregate value of common stock |  |  |  |  |  |  | $ 600,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
At the market stock offering program remaining amount available for issuance |  |  |  |  |  |  | 305,300,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Shares of its Common Stock in connection with the redemption of an equal number of OP Units |  |  |  | 333,997 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend payable date |  |  |  |  |  |  |  |  | Jan. 29, 2013 | Apr. 30, 2013 | Jul. 31, 2013 |  |  |  |  |  |  | May 15, 2013 | Aug. 15, 2013 |  |
Dividend paid on common stock (in dollars per share) | $ 0.65 |  | $ 0.65 |  |  |  |  |  |  |  |  | $ 17.8646 |  |  |  |  |  |  |  |  |
Dividend shareholder of record date |  |  |  |  |  |  |  |  | Dec. 31, 2012 | Mar. 29, 2013 | Jun. 28, 2013 |  |  |  |  |  |  |  | Aug. 05, 2013 |  |
Dividends payable, date declared |  |  |  |  |  |  |  |  |  |  | Jun. 18, 2013 |  |  |  |  |  |  |  | Jun. 18, 2013 |  |
Dividends Payable, Amount Per Share |  |  |  |  | $ 0.65 |  |  |  |  |  |  |  |  |  |  | $ 32.8125 |  |  |  |  |
Series B, Shares Outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 80,000 |  | 0 |  |  |  | 8,000,000
Series B, Dividend Rate, Percentage |  |  |  |  |  |  |  |  |  |  |  |  | 5.25% |  |  |  |  |  |  |  |
Series B, Liquidation Preference Per Share |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 2,500.00 | $ 2,500.00 |  | $ 0 |  |  | $ 25.00 | $ 25.00
Proceeds from Issuance of Series B |  | $ 193,900,000 |  | $ 193,920,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ratio of depository shares to shares of Series B Preferred Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.01 |  |  |  |  |  |
Shares issued in conjunction with exchange of 3.75% exchangeable senior notes |  |  |  |  |  |  |  | 419,116 |  |  |  |  |  |  |  |  |  |  |  |  |
Coupon/Stated Rate |  |  |  |  |  |  |  | 3.75% |  |  |  |  |  |  |  |  |  |  |  |  |

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