Summary of Significant Accounting Policies (Details 1) |
12 Months Ended |
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Dec. 31, 2017
Form
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| Cash and Cash Equivalents | |
| Maximum term until original maturity to classify cash and liquid investments as cash and cash equivalent (in months) | 3 months |
| Share-Based Compensation | |
| Number of forms of share based compensation plans | 3 |
| Corporate Office Properties, L.P. [Member] | |
| Noncontrolling Interest [Abstract] | |
| Interests in several real estate entities owned directly by COPT | 1.00% |
| X | ||||||||||
- Definition Represents the maximum term until original maturity to classify cash and liquid investments as cash and cash equivalents. No definition available.
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| X | ||||||||||
- Definition Percentage of ownership in noncontrolling interests generally not exceeded by Parent. No definition available.
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| X | ||||||||||
- Definition Number of Different Forms of Share Based Compensation No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- References No definition available.
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- Details
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