Document And Entity Information	3 Months Ended
	Mar. 31, 2013	Apr. 29, 2013 Common Class A [Member]	Apr. 29, 2013 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	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		19,413,818	0