    <SEC-DOCUMENT>0000860546-25-000045-index.html : 20251030
    <SEC-HEADER>0000860546-25-000045.hdr.sgml : 20251030
    <ACCEPTANCE-DATETIME>20251030162322
    ACCESSION NUMBER:		0000860546-25-000045
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		32
    CONFORMED PERIOD OF REPORT:	20251030
    ITEM INFORMATION:		Results of Operations and Financial Condition
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20251030
    DATE AS OF CHANGE:		20251030

    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
    		EIN:				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:		251435982

    	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>cdp-20251030.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: cdp-20251030.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>cdp09302025ex991.htm
    <DESCRIPTION>EX-99.1
    <TEXT>
    Document 2 - file: cdp09302025ex991.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>3
    <FILENAME>cdp-20251030.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 3 - file: cdp-20251030.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>4
    <FILENAME>cdp-20251030_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 4 - file: cdp-20251030_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>5
    <FILENAME>cdp-20251030_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 5 - file: cdp-20251030_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>a2025_q3xcoptdefensexcovera.jpg
    <TEXT>
    Document 6 - file: a2025_q3xcoptdefensexcovera.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>a8200-intxmarkjohnsonphotoa.jpg
    <TEXT>
    Document 7 - file: a8200-intxmarkjohnsonphotoa.jpg

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

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>chart-178e5f4205cd4ae9ae9a.jpg
    <TEXT>
    Document 9 - file: chart-178e5f4205cd4ae9ae9a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>chart-23fd775ec6a8437bad0a.jpg
    <TEXT>
    Document 10 - file: chart-23fd775ec6a8437bad0a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>chart-25e5c8ca0d1c4359933a.jpg
    <TEXT>
    Document 11 - file: chart-25e5c8ca0d1c4359933a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>chart-7f9b7ec21fae4944a55a.jpg
    <TEXT>
    Document 12 - file: chart-7f9b7ec21fae4944a55a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>chart-95807711f3ca43bd999a.jpg
    <TEXT>
    Document 13 - file: chart-95807711f3ca43bd999a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>chart-a9ca690fceb14b0cb08a.jpg
    <TEXT>
    Document 14 - file: chart-a9ca690fceb14b0cb08a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>chart-b10d18d587f0413f82ea.jpg
    <TEXT>
    Document 15 - file: chart-b10d18d587f0413f82ea.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>chart-b32c05329c664e439e5a.jpg
    <TEXT>
    Document 16 - file: chart-b32c05329c664e439e5a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>chart-d8069fbb5a89490589da.jpg
    <TEXT>
    Document 17 - file: chart-d8069fbb5a89490589da.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>chart-dbd91e87692643cebe4a.jpg
    <TEXT>
    Document 18 - file: chart-dbd91e87692643cebe4a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>chart-ec697b2dde234e8e916a.jpg
    <TEXT>
    Document 19 - file: chart-ec697b2dde234e8e916a.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>chart-f43baa6c217446d0a9ea.jpg
    <TEXT>
    Document 20 - file: chart-f43baa6c217446d0a9ea.jpg

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

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

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

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>24
    <FILENAME>suppbackcoverfinal-kp1a.jpg
    <TEXT>
    Document 24 - file: suppbackcoverfinal-kp1a.jpg

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

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>27
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 27 - file: Show.js

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

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>30
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 30 - file: FilingSummary.html

    Document 30 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>32
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 32 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>33
    <FILENAME>0000860546-25-000045-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 33 - file: 0000860546-25-000045-xbrl.zip

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>34
    <FILENAME>cdp-20251030_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 34 - file: cdp-20251030_htm.html

    Document 34 - RAW XML: cdp-20251030_htm.xml

    </DOCUMENT>
    </SEC-DOCUMENT>