Document And Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 30, 2014 Common Class A [Member]	Oct. 30, 2014 Common Class B [Member]
Document and Entity Information
Entity Registrant Name	CDI CORP
Entity Central Index Key	0000018396
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		19,619,764	0