| 
           Real Estate Transaction (Summary Of Office Property) (Details) (USD $) 
        In Thousands, unless otherwise specified  | 
        6 Months Ended | |||
|---|---|---|---|---|
| 
           Jun. 30, 2011 
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| # of Bldgs. | 1 | |||
| Rentable Square Feet | 204,057 | |||
| 
           55 Corporate [Member] 
         | 
        ||||
| Date | 05/01/11 | |||
| Property/Address | 55 Corporate Drive | |||
| Location | Bridgewater, New Jersey | |||
| # of Bldgs. | 1 | |||
| Rentable Square Feet | 204,057 | |||
| Investment by Company | $ 45,913 | [1] | ||
          
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          Number Of Properties Placed In Service 
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          Real Estate Property Initial Operations Commenced, Date 
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| X | ||||||||||
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          Real Estate Property Located Address 
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          Real Estate Property Location 
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          Square Feet 
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- Definition 
          Investments in real estate held solely for investment purposes (income production and capital appreciation). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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