| Noncontrolling Interests In Subsidiaries (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified | 9 Months Ended | |
|---|---|---|
| Sep. 30, 2013 | Dec. 31, 2012 | |
| Noncontrolling Interest [Line Items] | ||
| Number of common shares received upon redemption of common units | 1 | |
| Rebalance of ownership percentage | $ 0.5 | |
| Percentage of noncontrolling interest | 12.00% | 12.20% | 
| Participation Rights [Member] | ||
| Noncontrolling Interest [Line Items] | ||
| Excess net cash flow remaining after the distribution to the Company | 50.00% | |
| Internal rate of return | 10.00% | |
| Office Buildings [Member] | Participation Rights [Member] | ||
| Noncontrolling Interest [Line Items] | ||
| Number of properties | 3 | 
| X | ||||||||||
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- Definition Distribution of cash flow to individual companies percentage No definition available. 
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- Definition Internal Rate of Return No definition available. 
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- Definition Number Of Common Shares Received Upon Redemption Of Common Units No definition available. 
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- Definition Rebalance Of Ownership Percentage No definition available. 
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- Details 
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- Definition The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity. No definition available. 
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- Definition The number of real estate properties owned as of the balance sheet date. No definition available. 
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