Impaired Financing Receivable, Impairment analysis performed percent

No definition available.

Name:	agm_ImpairedFinancingReceivableImpairmentAnalysisPerformedPercent
Namespace Prefix:	agm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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_FinancingReceivableImpairedLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableInterestIncomeCashBasisMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953550-111524

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

Name:	us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	agm_PaymentStatusOfLoanOrLoansHeldInSecuritiesAxis=agm_LessThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_CropsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_PermanentPlantingsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_LivestockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_PartTimeFarmMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_AgricultureStorageAndProcessingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_CommodityByTypeAxis=agm_OtherCommodityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	agm_ImpairmentAnalysisAxis=agm_CollateralDependentNotIndividuallyAnalyzedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans - Schedule of Impaired Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				$ 52,191
Impaired loans, with no specific allowance, unpaid principal balance				52,014
Impaired loan, with a specific allowance, recorded investment				174,385
Impaired loans, with a specific allowance, unpaid principal balance				173,844
Impaired loans, associated allowance				6,541
Recorded investment				226,576
Unpaid principal balance				225,858
Recorded investment of loans on nonaccrual status			$ 129,439	87,781
Average recorded investment in impaired loans	$ 196,914	$ 173,943
Income recognized on impaired loans	536	2,196
Less than 90 days past due
Financing Receivable, Impaired [Line Items]
Recorded investment of loans on nonaccrual status				30,100
Crops
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				30,846
Impaired loans, with no specific allowance, unpaid principal balance				30,741
Impaired loan, with a specific allowance, recorded investment				84,044
Impaired loans, with a specific allowance, unpaid principal balance				83,772
Impaired loans, associated allowance				2,725
Recorded investment				114,890
Unpaid principal balance				114,513
Recorded investment of loans on nonaccrual status				34,037
Average recorded investment in impaired loans	106,535	93,088
Income recognized on impaired loans	178	879
Permanent Plantings
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				16,696
Impaired loans, with no specific allowance, unpaid principal balance				16,638
Impaired loan, with a specific allowance, recorded investment				36,852
Impaired loans, with a specific allowance, unpaid principal balance				36,732
Impaired loans, associated allowance				1,051
Recorded investment				53,548
Unpaid principal balance				53,370
Recorded investment of loans on nonaccrual status				22,849
Average recorded investment in impaired loans	45,197	41,524
Income recognized on impaired loans	166	586
Livestock
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				3,195
Impaired loans, with no specific allowance, unpaid principal balance				3,185
Impaired loan, with a specific allowance, recorded investment				47,113
Impaired loans, with a specific allowance, unpaid principal balance				46,984
Impaired loans, associated allowance				2,636
Recorded investment				50,308
Unpaid principal balance				50,169
Recorded investment of loans on nonaccrual status				28,441
Average recorded investment in impaired loans	36,859	31,189
Income recognized on impaired loans	87	504
Part-time Farm
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				1,398
Impaired loans, with no specific allowance, unpaid principal balance				1,394
Impaired loan, with a specific allowance, recorded investment				6,376
Impaired loans, with a specific allowance, unpaid principal balance				6,356
Impaired loans, associated allowance				129
Recorded investment				7,774
Unpaid principal balance				7,750
Recorded investment of loans on nonaccrual status				2,454
Average recorded investment in impaired loans	8,265	8,079
Income recognized on impaired loans	105	227
Ag. Storage and Processing
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				0
Impaired loans, with no specific allowance, unpaid principal balance				0
Impaired loan, with a specific allowance, recorded investment				0
Impaired loans, with a specific allowance, unpaid principal balance				0
Impaired loans, associated allowance				0
Recorded investment				0
Unpaid principal balance				0
Recorded investment of loans on nonaccrual status				0
Average recorded investment in impaired loans	0	0
Income recognized on impaired loans	0	0
Other
Financing Receivable, Impaired [Line Items]
Impaired loans, with no specific allowance, recorded investment				56
Impaired loans, with no specific allowance, unpaid principal balance				56
Impaired loan, with a specific allowance, recorded investment				0
Impaired loans, with a specific allowance, unpaid principal balance				0
Impaired loans, associated allowance				0
Recorded investment				56
Unpaid principal balance				56
Recorded investment of loans on nonaccrual status				0
Average recorded investment in impaired loans	58	63
Income recognized on impaired loans	$ 0	$ 0
Collateral Dependent Not Individually Analyzed
Financing Receivable, Impaired [Line Items]
Impaired loans, associated allowance				3,000
Recorded investment				$ 159,100
Impaired loans, impairment analysis performed percent				70.00%