XML 55 R37.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Share-Based Compensation (Tables) | 6 Months Ended
--- | ---
Jun. 30, 2018
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 PSUs earned (“earned PSUs”) 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 PSUs Payout %
75th or greater |  | 200% of PSUs granted
50th |  | 100% of PSUs granted
25th |  | 50% of PSUs granted
Below 25th |  | 0% of PSUs granted

X
- Definition Schedule of payouts for defined performance under performance-based awards of share-based compensation + References No definition available. + Details
Name: | ofc_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardForDefinedPerformanceTableTextBlock
Namespace Prefix: | ofc_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration