Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Details 1)

v3.6.0.2
Summary of Significant Accounting Policies (Details 1)
12 Months Ended
Dec. 31, 2016
Form
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%