    <SEC-DOCUMENT>0000860546-24-000058-index.html : 20241028
    <SEC-HEADER>0000860546-24-000058.hdr.sgml : 20241028
    <ACCEPTANCE-DATETIME>20241028162554
    ACCESSION NUMBER:		0000860546-24-000058
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		33
    CONFORMED PERIOD OF REPORT:	20241028
    ITEM INFORMATION:		Results of Operations and Financial Condition
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20241028
    DATE AS OF CHANGE:		20241028

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			COPT DEFENSE PROPERTIES
    		CENTRAL INDEX KEY:			0000860546
    		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
    		ORGANIZATION NAME:           	05 Real Estate & Construction
    		IRS NUMBER:				232947217
    		STATE OF INCORPORATION:			MD
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-14023
    		FILM NUMBER:		241401243

    	BUSINESS ADDRESS:
    		STREET 1:		6711 COLUMBIA GATEWAY DRIVE
    		STREET 2:		SUITE 300
    		CITY:			COLUMBIA
    		STATE:			MD
    		ZIP:			21046
    		BUSINESS PHONE:		4432855400

    	MAIL ADDRESS:
    		STREET 1:		6711 COLUMBIA GATEWAY DRIVE
    		STREET 2:		SUITE 300
    		CITY:			COLUMBIA
    		STATE:			MD
    		ZIP:			21046

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CORPORATE OFFICE PROPERTIES TRUST
    		DATE OF NAME CHANGE:	19980514

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CORPORATE OFFICE PROPERTIES TRUST INC
    		DATE OF NAME CHANGE:	19980105

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ROYALE INVESTMENTS INC
    		DATE OF NAME CHANGE:	19930328
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>ofc-20241028.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: ofc-20241028.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>cdp09302024ex991.htm
    <DESCRIPTION>EX-99.1
    <TEXT>
    Document 2 - file: cdp09302024ex991.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>3
    <FILENAME>ofc-20241028.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 3 - file: ofc-20241028.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>4
    <FILENAME>ofc-20241028_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 4 - file: ofc-20241028_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>5
    <FILENAME>ofc-20241028_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 5 - file: ofc-20241028_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>a2024_q3xcoptdefensexcover.jpg
    <TEXT>
    Document 6 - file: a2024_q3xcoptdefensexcover.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>cdplogo.jpg
    <TEXT>
    Document 7 - file: cdplogo.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>chart-0ffffa3e6399420b924.jpg
    <TEXT>
    Document 8 - file: chart-0ffffa3e6399420b924.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>chart-54efb4e524c045beaf1.jpg
    <TEXT>
    Document 9 - file: chart-54efb4e524c045beaf1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>chart-619508e79c0a4a46a0f.jpg
    <TEXT>
    Document 10 - file: chart-619508e79c0a4a46a0f.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>chart-7375c8fe663c4457b23.jpg
    <TEXT>
    Document 11 - file: chart-7375c8fe663c4457b23.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>chart-7e3bb94f155b4f459ba.jpg
    <TEXT>
    Document 12 - file: chart-7e3bb94f155b4f459ba.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>chart-8a79a5de70424eeda08.jpg
    <TEXT>
    Document 13 - file: chart-8a79a5de70424eeda08.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>chart-9cb4d45ad218408daba.jpg
    <TEXT>
    Document 14 - file: chart-9cb4d45ad218408daba.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>chart-a4b62acdcd87476399e.jpg
    <TEXT>
    Document 15 - file: chart-a4b62acdcd87476399e.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>chart-b1b8a389c0ca4171bb4.jpg
    <TEXT>
    Document 16 - file: chart-b1b8a389c0ca4171bb4.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>chart-c364850d05dd49faa4d.jpg
    <TEXT>
    Document 17 - file: chart-c364850d05dd49faa4d.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>chart-cd8f4172972245f0a21.jpg
    <TEXT>
    Document 18 - file: chart-cd8f4172972245f0a21.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>chart-f5f0a32414324bcf941.jpg
    <TEXT>
    Document 19 - file: chart-f5f0a32414324bcf941.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>erheader.jpg
    <TEXT>
    Document 20 - file: erheader.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>forimmediaterelease.jpg
    <TEXT>
    Document 21 - file: forimmediaterelease.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>22
    <FILENAME>newcoptlogohorizontaljpg.jpg
    <TEXT>
    Document 22 - file: newcoptlogohorizontaljpg.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>23
    <FILENAME>suppbackcoverfinal-kp1.jpg
    <TEXT>
    Document 23 - file: suppbackcoverfinal-kp1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>24
    <FILENAME>waylineofficescolumbiamd_2.jpg
    <TEXT>
    Document 24 - file: waylineofficescolumbiamd_2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>26
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 26 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>27
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 27 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>28
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 28 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>29
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 29 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>31
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 31 - file: FilingSummary.html

    Document 31 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>33
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 33 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>34
    <FILENAME>0000860546-24-000058-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 34 - file: 0000860546-24-000058-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>35
    <FILENAME>ofc-20241028_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 35 - file: ofc-20241028_htm.html

    Document 35 - RAW XML: ofc-20241028_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>