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Share-Based Compensation (Tables) | 3 Months Ended
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Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Schedule of payouts for defined performance under performance-based awards of share-based compensation | The number of earned awards at the end of the performance period will be determined based on the percentile rank of COPT’s total shareholder return relative to a peer group of companies, as set forth in the following schedule:
Percentile Rank |  | Earned Awards Payout %
75th or greater |  | 100% of PB-PIUs granted
50th (target) |  | 50% of PB-PIUs granted
25th |  | 25% of PB-PIUs granted
Below 25th |  | 0% of PB-PIUs granted

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- Definition Schedule of payouts for defined performance under performance-based awards of share-based compensation + References No definition available. + Details
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