v2.4.0.8

Organization (Details) (USD $) | 6 Months Ended |  | 60 Months Ended |  |  |  | 3 Months Ended |  |
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Jun. 30, 2013 Y acre Vehicles sqft | Jun. 30, 2012 | Jun. 30, 2013 Commercial Real Estate Properties [Member] sqft Real_Estate_Properties | Jun. 30, 2013 Total Properties Under Construction [ Member] Real_Estate_Properties sqft | Jun. 30, 2013 Total Office Properties [ Member] Real_Estate_Properties | Jun. 30, 2013 Class A Office Properties [Member] Real_Estate_Properties | Jun. 30, 2013 Office Properties Under Construction [ Member] Real_Estate_Properties | Jun. 30, 2013 Office Technical Properties [Member] Real_Estate_Properties | Jun. 30, 2013 Hotel Property [ Member] Real_Estate_Properties | Jun. 30, 2013 Retail Properties [ Member] Real_Estate_Properties | Jun. 30, 2013 Residential Properties [Member] Real_Estate_Properties | Jun. 30, 2013 Residential Properties Under Construction [Member] Real_Estate_Properties | Mar. 26, 2018 Series B Cumulative Redeemable Preferred Stock [Member] | Jun. 30, 2013 Series B Cumulative Redeemable Preferred Stock [Member] | Dec. 31, 2012 Series B Cumulative Redeemable Preferred Stock [Member] | Jun. 30, 2013 Depository shares of Series B Cumulative Redeemable Preferred [Member] | Jun. 30, 2013 Series Two Preferred Units [Member] | Jun. 30, 2013 series four preferred units [Member] | Aug. 07, 2013 series four preferred units [Member] | Jun. 30, 2013 Series B Preferred Units [Member]
Real Estate Properties [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
General and limited partnership interest in the operating partnership (percent) | 89.20% | 88.50% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restriction on redemption of OP units from date of issuance (years) | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
One OP unit is equivalent to one share of Common Stock (in shares) | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
OP unit conversion rate (in shares) | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series B, Shares Outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  | 80,000 | 0 | 8,000,000 |  |  |  | 80,000
Series B, Dividend Rate, Percentage |  |  |  |  |  |  |  |  |  |  |  |  | 5.25% |  |  |  |  |  |  |
Number Of Series Of Preferred Units Outstanding | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
OP Units for each Preferred Unit (in shares) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.312336 |  |  |
Preferred Units Liquidation Preference |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 50.00 | $ 50.00 | $ 50.00 |
Quarterly Distributions to Series Four Preferred Units |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.25 |  |
Series Four Preferred Units Annual Dividend Payable Rate |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.00% |  |
Number of real estate properties |  |  | 179 | 8 | 171 | 131 | 7 | 40 | 1 | 4 | 3 | 1 |  |  |  |  |  |  |  |
Net Rentable Area |  |  | 44,800,000 | 2,800,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of vehicles in structured parking | 46,411 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of parking (in square feet) | 15,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of undeveloped land parcels owned (in acres) | 512.8 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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