Loans and Allowance for Losses and Concentrations of Credit Risk Financing Receivables Credit Quality Indicators (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	$ 4,917,489	[1]	$ 4,747,289	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	33,922	[1]	33,263	[2]
Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,400,229	[1]	2,171,349	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	7,939	[1]	4,668	[2]
Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	886,334	[1]	882,532	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	16,217	[1]	10,801	[2]
Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,240,610	[1]	1,287,741	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,229	[1]	7,222	[2]
Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	178,261	[1]	201,865	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,418	[1]	6,118	[2]
Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	201,180	[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	10,875	[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	1,876,958	[1]	1,679,851	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	27,469	[1]	29,592	[2]
On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,178,599	[1]	999,566	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	4,516	[1]	3,971	[2]
On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	313,757	[1]	289,694	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	16,000	[1]	10,756	[2]
On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	285,643	[1]	280,380	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,853	[1]	4,389	[2]
On-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	56,401	[1]	62,947	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,981	[1]	6,022	[2]
On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	40,797	[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	1,761	[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	3,040,531	[1]	3,067,438	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,453	[1]	3,671	[2]
Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,221,630	[1]	1,171,783	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,423	[1]	697	[2]
Off-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	572,577	[1]	592,838	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	217	[1]	45	[2]
Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	954,967	[1]	1,007,361	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,376	[1]	2,833	[2]
Off-balance sheet [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	121,860	[1]	138,918	[1]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	437	[1]	96	[2]
Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	160,383	[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	9,114	[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	4,589,885	[1]	4,374,938	[1]
Pass [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,317,516	[1]	2,090,887	[1]
Pass [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	816,817	[1]	793,317	[1]
Pass [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,144,009	[1]	1,174,779	[1]
Pass [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	158,626	[1]	178,713	[1]
Pass [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	142,855	[1]	126,955	[1]
Pass [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	10,062	[1]	10,287	[1]
Pass [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,714,649	[1]	1,486,003	[1]
Pass [Member] | On-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,129,443	[1]	947,097	[1]
Pass [Member] | On-balance sheet [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	266,597	[1]	226,253	[1]
Pass [Member] | On-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	261,983	[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	43,519	[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	11,461	[1]	11,972	[1]
Pass [Member] | On-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,646	[1]	0	[1]
Pass [Member] | Off-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	2,875,236	[1]	2,888,935	[1]
Pass [Member] | Off-balance sheet [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	1,188,073	[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	550,220	[1]	567,064	[1]
Pass [Member] | Off-balance sheet [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	882,026	[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	115,107	[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	131,394	[1]	114,983	[1]
Pass [Member] | Off-balance sheet [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	8,416	[1]	10,287	[1]
Special Mention [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	126,065	[1],[3]	185,837	[1],[3]
Special Mention [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	32,387	[1],[3]	40,925	[1],[3]
Special Mention [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	21,765	[1],[3]	38,862	[1],[3]
Special Mention [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	49,173	[1],[3]	56,754	[1],[3]
Special Mention [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	5,212	[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	16,937	[1],[3]	43,353	[1],[3]
Special Mention [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	591	[1],[3]	592	[1],[3]
Special Mention [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	66,718	[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	26,177	[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	13,513	[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	13,722	[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	3,289	[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	10,017	[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	59,347	[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	6,210	[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	8,252	[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	35,451	[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	1,923	[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	6,920	[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	591	[1],[3]	592	[1],[3]
Substandard [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	201,539	[1],[3]	186,514	[1],[3]
Substandard [Member] | Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	50,326	[1],[3]	39,537	[1],[3]
Substandard [Member] | Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	47,752	[1],[3]	50,353	[1],[3]
Substandard [Member] | Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	47,428	[1],[3]	56,208	[1],[3]
Substandard [Member] | Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	14,423	[1],[3]	17,801	[1],[3]
Substandard [Member] | Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	41,388	[1],[3]	21,478	[1],[3]
Substandard [Member] | Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	222	[1],[3]	1,137	[1],[3]
Substandard [Member] | On-balance sheet [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Gross	95,591	[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	22,979	[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	33,647	[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	9,938	[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	9,593	[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	19,319	[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	105,948	[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	27,347	[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	14,105	[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	37,490	[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	4,830	[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	22,069	[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	$ 107	[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.