XML 107 R93.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Employee Benefits - Employee Benefits (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Contribution Plan Wage Base | $ 265,000 | $ 265,000 | $ 260,000
Deferred Compensation Arrangement with Individual, Requisite Service Period | 3 years |  |
Defined Contribution Plan, Cost Recognized | $ 1,300,000 | $ 1,200,000 | $ 1,200,000
Base Percentage [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contribution percentage to retirement plan | 13.20% |  |
Excess Percentage for amounts above Social Security taxable wage base] [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Employer contribution percentage to retirement plan | 5.70% |  |

X
- Definition Defined Contribution Plan Wage Base + References No definition available. + Details
Name: | agm_DefinedContributionPlanWageBase
Namespace Prefix: | agm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Employer contribution percentage to retirement plan + References No definition available. + Details
Name: | agm_Employercontributionpercentagetoretirementplan
Namespace Prefix: | agm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum period the individual is required to perform services to be fully vested under the deferred compensation arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6409961&loc=d3e20487-108367 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualRequisiteServicePeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedContributionPlanNameAxis=agm_BasePercentageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedContributionPlanNameAxis=agm_ExcessPercentageforamountsaboveSocialSecuritytaxablewagebaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |