Document And Entity Information	6 Months Ended
	Jun. 30, 2011	Aug. 02, 2011 Class A Common Stock [Member]	Aug. 02, 2011 Class B Common Stock [Member]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Entity Registrant Name	BGC Partners, Inc.
Entity Central Index Key	0001094831
Trading Symbol	bgcp
Entity Filer Category	Accelerated Filer
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		88,245,112	34,848,107