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Properties, net (Details 5) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2012 | Jun. 30, 2012 | Mar. 31, 2012 | Sep. 30, 2012
Properties |  |  |  |
Impairment losses | $ 55,829 | $ 2,354 | $ 6,587 | $ 64,770
Operating properties, net |  |  |  |
Properties |  |  |  |
Impairment losses | 55,829 | 2,354 | 11,833 | 70,016
Non-operating Properties |  |  |  |
Properties |  |  |  |
Impairment losses | $ 0 | $ 0 | $ (5,246) | $ (5,246)

X
- Definition The charge against earnings from continuing and noncontinuing operations resulting from the aggregate write down of all assets from their carrying value to their fair value. + References No definition available. + Details
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Namespace Prefix: | ofc_
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Balance Type: | debit
Period Type: | duration

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- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration