Loans and Allowance for Losses and Concentrations of Credit Risk - Financing Receivables Credit Quality Indicators (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	$ 5,035,748	[1]	$ 4,747,289	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	33,042	[1]	33,263	[2]
Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,531,923	[1]	2,171,349	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,019	[1]	4,668	[2]
Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	905,613	[1]	882,532	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	17,040	[1]	10,801	[2]
Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,239,589	[1]	1,287,741	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,537	[1]	7,222	[2]
Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	169,455	[1]	201,865	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,327	[1]	6,118	[2]
Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	179,627	[1]	191,786	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[1]	4,337	[2]
Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	9,541	[1]	12,016	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	119	[1]	117	[2]
On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,950,703	[1]	1,679,851	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	32,711	[1]	29,592	[2]
On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,252,027	[1]	999,566	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	5,799	[1]	3,971	[2]
On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	313,922	[1]	289,694	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	17,001	[1]	10,756	[2]
On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	291,346	[1]	280,380	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,537	[1]	4,389	[2]
On-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	53,044	[1]	62,947	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,255	[1]	6,022	[2]
On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	39,690	[1]	47,149	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[1]	4,337	[2]
On-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	674	[1]	115	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	119	[1]	117	[2]
Off-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	3,085,045	[1]	3,067,438	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	331	[1]	3,671	[2]
Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,279,896	[1]	1,171,783	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	220	[1]	697	[2]
Off-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	591,691	[1]	592,838	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	39	[1]	45	[2]
Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	948,243	[1]	1,007,361	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[1]	2,833	[2]
Off-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	116,411	[1]	138,918	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	72	[1]	96	[2]
Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	139,937	[1]	144,637	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[1]	0	[2]
Off-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	8,867	[1]	11,901	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[1]	0	[2]
Pass [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	4,741,840	[1]	4,374,938	[1]
Pass [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,477,914	[1]	2,090,887	[1]
Pass [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	841,348	[1]	793,317	[1]
Pass [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,151,662	[1]	1,174,779	[1]
Pass [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	150,278	[1]	178,713	[1]
Pass [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	111,903	[1]	126,955	[1]
Pass [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	8,735	[1]	10,287	[1]
Pass [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,832,372	[1]	1,486,003	[1]
Pass [Member] | On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,228,416	[1]	947,097	[1]
Pass [Member] | On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	273,869	[1]	226,253	[1]
Pass [Member] | On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	277,058	[1]	252,525	[1]
Pass [Member] | On-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	41,222	[1]	48,156	[1]
Pass [Member] | On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	11,248	[1]	11,972	[1]
Pass [Member] | On-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	559	[1]	0	[1]
Pass [Member] | Off-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,909,468	[1]	2,888,935	[1]
Pass [Member] | Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,249,498	[1]	1,143,790	[1]
Pass [Member] | Off-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	567,479	[1]	567,064	[1]
Pass [Member] | Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	874,604	[1]	922,254	[1]
Pass [Member] | Off-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	109,056	[1]	130,557	[1]
Pass [Member] | Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	100,655	[1]	114,983	[1]
Pass [Member] | Off-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	8,176	[1]	10,287	[1]
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	102,325	[1],[3]	185,837	[1],[3]
Special Mention [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	9,237	[1],[3]	40,925	[1],[3]
Special Mention [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	18,285	[1],[3]	38,862	[1],[3]
Special Mention [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	42,120	[1],[3]	56,754	[1],[3]
Special Mention [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	3,469	[1],[3]	5,351	[1],[3]
Special Mention [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	28,629	[1],[3]	43,353	[1],[3]
Special Mention [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	585	[1],[3]	592	[1],[3]
Special Mention [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	24,992	[1],[3]	102,716	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,598	[1],[3]	30,466	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	7,904	[1],[3]	33,794	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	3,228	[1],[3]	16,344	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,431	[1],[3]	2,131	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	9,831	[1],[3]	19,981	[1],[3]
Special Mention [Member] | On-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	0	[1],[3]	0	[1],[3]
Special Mention [Member] | Off-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	77,333	[1],[3]	83,121	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	6,639	[1],[3]	10,459	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	10,381	[1],[3]	5,068	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	38,892	[1],[3]	40,410	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,038	[1],[3]	3,220	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	18,798	[1],[3]	23,372	[1],[3]
Special Mention [Member] | Off-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	585	[1],[3]	592	[1],[3]
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	191,583	[1],[3]	186,514	[1],[3]
Substandard [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	44,772	[1],[3]	39,537	[1],[3]
Substandard [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	45,980	[1],[3]	50,353	[1],[3]
Substandard [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	45,807	[1],[3]	56,208	[1],[3]
Substandard [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	15,708	[1],[3]	17,801	[1],[3]
Substandard [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	39,095	[1],[3]	21,478	[1],[3]
Substandard [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	221	[1],[3]	1,137	[1],[3]
Substandard [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	93,339	[1],[3]	91,132	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	21,013	[1],[3]	22,003	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	32,149	[1],[3]	29,647	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	11,060	[1],[3]	11,511	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	10,391	[1],[3]	12,660	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	18,611	[1],[3]	15,196	[1],[3]
Substandard [Member] | On-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	115	[1],[3]	115	[1],[3]
Substandard [Member] | Off-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	98,244	[1],[3]	95,382	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	23,759	[1],[3]	17,534	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	13,831	[1],[3]	20,706	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	34,747	[1],[3]	44,697	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	5,317	[1],[3]	5,141	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	20,484	[1],[3]	6,282	[1],[3]
Substandard [Member] | Off-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	$ 106	[1],[3]	$ 1,022	[1],[3]

[1] Amounts represent unpaid principal balance of risk-rated loans, which is the basis Farmer Mac uses to analyze its portfolio, and recorded investment of past due loans.

[2] (1)Amounts represent unpaid principal balance of risk-rated loans, which is the basis Farmer Mac uses to analyze its portfolio, and recorded investment of past due loans.

[3] Assets in the OAEM category generally have potential weaknesses due to performance issues but are currently considered to be adequately secured. Substandard assets have a well-defined weakness or weaknesses and there is a distinct possibility that some loss will be sustained if deficiencies are not corrected.