XML 112 R51.htm IDEA: XBRL DOCUMENT v2.4.1.9
Related Party Transactions - Narrative (Details)
 12 Months Ended
Dec. 31, 2014
Related Party Transaction [Line Items]  
Common Stock Ownership Percentage by a Related Party 5.00%agm_CommonStockOwnershipPercentageByRelatedParty
Number of Board of Directors 15agm_NumberOfBoardOfDirectors
Common Class A, Voting [Member]  
Related Party Transaction [Line Items]  
Number of Board of Directors 5agm_NumberOfBoardOfDirectors
/ agm_ElectedByAxis
= us-gaap_CommonClassAMember
Common Class B, Voting [Member]  
Related Party Transaction [Line Items]  
Number of Board of Directors 5agm_NumberOfBoardOfDirectors
/ agm_ElectedByAxis
= us-gaap_CommonClassBMember