Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Jun. 30, 2011	Mar. 01, 2012 Common Stock, Class A Voting	Mar. 01, 2012 Common stock, Class B Voting	Mar. 01, 2012 Common stock, Class C Non-Voting
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Trading Symbol	AGM
Entity Registrant Name	FEDERAL AGRICULTURAL MORTGAGE CORP
Entity Central Index Key	0000845877
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding			1,030,780	500,301	8,832,485
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$ 210,270,506