Loans and Allowance for Losses and Concentrations of Credit Risk - Financing Receivables Credit Quality Indicators (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Impaired, Loans Past Due Period, Minimum	90 days
Financing Receivable, Gross	$ 5,314,437	[1],[2]	$ 5,163,080	[1],[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	24,661	[2]	28,296	[3]
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	5,069,151	[2]	4,845,302	[2]
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	115,132	[2],[4]	122,830	[2],[4]
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	130,154	[2],[5]	194,948	[2],[5]
On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,380,448	[2]	2,135,467	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	21,409	[2]	27,580	[3]
On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,267,875	[2]	1,988,945	[2]
On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	40,037	[2],[4]	47,171	[2],[4]
On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	72,536	[2],[5]	99,351	[2],[5]
Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,933,989	[2]	3,027,613	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,252	[2]	716	[3]
Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,801,276	[2]	2,856,357	[2]
Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	75,095	[2],[4]	75,659	[2],[4]
Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	57,618	[2],[5]	95,597	[2],[5]
Crops [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,880,245	[2]	2,666,857	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	7,700	[2]	8,256	[3]
Crops [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,812,053	[2]	2,600,039	[2]
Crops [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	42,848	[2],[4]	26,633	[2],[4]
Crops [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	25,344	[2],[5]	40,185	[2],[5]
Crops [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,542,806	[2]	1,385,008	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,923	[2]	8,036	[3]
Crops [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,499,552	[2]	1,348,205	[2]
Crops [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	29,011	[2],[4]	15,656	[2],[4]
Crops [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	14,243	[2],[5]	21,147	[2],[5]
Crops [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,337,439	[2]	1,281,849	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	777	[2]	220	[3]
Crops [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,312,501	[2]	1,251,834	[2]
Crops [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	13,837	[2],[4]	10,977	[2],[4]
Crops [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	11,101	[2],[5]	19,038	[2],[5]
Permanent Plantings [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	905,081	[2]	907,824	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,861	[2]	11,841	[3]
Permanent Plantings [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	841,791	[2]	838,318	[2]
Permanent Plantings [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	13,580	[2],[4]	20,594	[2],[4]
Permanent Plantings [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	49,710	[2],[5]	48,912	[2],[5]
Permanent Plantings [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	373,827	[2]	336,478	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,861	[2]	11,841	[3]
Permanent Plantings [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	332,340	[2]	290,064	[2]
Permanent Plantings [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,172	[2],[4]	4,973	[2],[4]
Permanent Plantings [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	40,315	[2],[5]	41,441	[2],[5]
Permanent Plantings [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	531,254	[2]	571,346	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	0	[3]
Permanent Plantings [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	509,451	[2]	548,254	[2]
Permanent Plantings [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	12,408	[2],[4]	15,621	[2],[4]
Permanent Plantings [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	9,395	[2],[5]	7,471	[2],[5]
Livestock [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,247,390	[2]	1,246,105	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	6,677	[2]	4,462	[3]
Livestock [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,173,880	[2]	1,144,438	[2]
Livestock [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	48,882	[2],[4]	55,912	[2],[4]
Livestock [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	24,628	[2],[5]	45,755	[2],[5]
Livestock [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	383,762	[2]	330,509	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	4,915	[2]	4,462	[3]
Livestock [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	367,631	[2]	300,308	[2]
Livestock [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	8,895	[2],[4]	19,357	[2],[4]
Livestock [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	7,236	[2],[5]	10,844	[2],[5]
Livestock [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	863,628	[2]	915,596	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	1,762	[2]	0	[3]
Livestock [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	806,249	[2]	844,130	[2]
Livestock [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	39,987	[2],[4]	36,555	[2],[4]
Livestock [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	17,392	[2],[5]	34,911	[2],[5]
Part-Time Farm [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	152,915	[2]	162,743	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	3,423	[2]	3,618	[3]
Part-Time Farm [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	134,159	[2]	144,611	[2]
Part-Time Farm [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	2,634	[2],[4]	1,835	[2],[4]
Part-Time Farm [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	16,122	[2],[5]	16,297	[2],[5]
Part-Time Farm [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	49,821	[2]	50,362	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	2,710	[2]	3,122	[3]
Part-Time Farm [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	38,120	[2]	39,022	[2]
Part-Time Farm [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	959	[2],[4]	918	[2],[4]
Part-Time Farm [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	10,742	[2],[5]	10,422	[2],[5]
Part-Time Farm [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	103,094	[2]	112,381	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	713	[2]	496	[3]
Part-Time Farm [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	96,039	[2]	105,589	[2]
Part-Time Farm [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	1,675	[2],[4]	917	[2],[4]
Part-Time Farm [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	5,380	[2],[5]	5,875	[2],[5]
Agriculture Storage and Processing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	120,876	[2]	170,918	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	0	[3]
Agriculture Storage and Processing [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	99,996	[2]	110,059	[2]
Agriculture Storage and Processing [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	6,630	[2],[4]	17,278	[2],[4]
Agriculture Storage and Processing [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	14,250	[2],[5]	43,581	[2],[5]
Agriculture Storage and Processing [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	29,635	[2]	32,636	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	0	[3]
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	29,635	[2]	10,987	[2]
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	0	[2],[4]	6,267	[2],[4]
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	0	[2],[5]	15,382	[2],[5]
Agriculture Storage and Processing [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	91,241	[2]	138,282	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	0	[3]
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	70,361	[2]	99,072	[2]
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	6,630	[2],[4]	11,011	[2],[4]
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	14,250	[2],[5]	28,199	[2],[5]
Other Commodity [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	7,930	[2]	8,633	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	119	[3]
Other Commodity [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	7,272	[2]	7,837	[2]
Other Commodity [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	558	[2],[4]	578	[2],[4]
Other Commodity [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	100	[2],[5]	218	[2],[5]
Other Commodity [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	597	[2]	474	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	119	[3]
Other Commodity [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	597	[2]	359	[2]
Other Commodity [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	0	[2],[4]	0	[2],[4]
Other Commodity [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	0	[2],[5]	115	[2],[5]
Other Commodity [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	7,333	[2]	8,159	[2]
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	0	[2]	0	[3]
Other Commodity [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	6,675	[2]	7,478	[2]
Other Commodity [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	558	[2],[4]	578	[2],[4]
Other Commodity [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	$ 100	[2],[5]	$ 103	[2],[5]

[1] Geographic regions: Northwest (AK, ID, MT, OR, WA, WY); Southwest (AZ, CA, CO, HI, NM, NV, UT); Mid-North (IA, IL, IN, MI, MN, NE, ND, SD, WI); Mid-South (AR, KS, LA, MO, OK, TX); Northeast (CT, DE, KY, MA, MD, ME, NH, NJ, NY, OH, PA, RI, VA, VT, WV); Southeast (AL, FL, GA, MS, NC, SC, TN).

[2] 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] (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.

[4] Assets in the Special mention category generally have potential weaknesses due to performance issues but are currently considered to be adequately secured.

[5] 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.