Loans and Allowance for Losses and Concentrations of Credit Risk - Financing Receivables Credit Quality Indicators (Details) - USD ($) $ in Thousands		Sep. 30, 2015		Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[2]	$ 5,504,030		$ 5,417,174
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	[3]	36,669	[1]	18,917	[4]
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	5,256,586		5,172,691
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	125,344		111,888
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	122,100		132,595
On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	2,778,692		2,540,222
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	[3]	17,967	[1]	18,427	[4]
On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	2,653,535		2,419,285
On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	61,763		54,495
On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	63,394		66,442
Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	2,725,338		2,876,952
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due	[3]	18,702	[1]	490	[4]
Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	2,603,051		2,753,406
Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	63,581		57,393
Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	58,706		66,153
Crops [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	3,054,452		2,941,266
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		6,901	[1]	4,175	[4]
Crops [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	2,965,117		2,887,319
Crops [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	55,565		30,417
Crops [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	33,770		23,530
Crops [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,791,855		1,633,667
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		6,209	[1]	4,175	[4]
Crops [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,753,713		1,604,546
Crops [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	17,302		16,814
Crops [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	20,840		12,307
Crops [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,262,597		1,307,599
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		692	[1]	0	[4]
Crops [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,211,404		1,282,773
Crops [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	38,263		13,603
Crops [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	12,930		11,223
Permanent Plantings [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	930,659		920,195
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		8,729	[1]	6,869	[4]
Permanent Plantings [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	882,791		856,901
Permanent Plantings [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	12,570		18,180
Permanent Plantings [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	35,298		45,114
Permanent Plantings [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	426,052		395,421
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		8,729	[1]	6,869	[4]
Permanent Plantings [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	396,674		353,487
Permanent Plantings [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	136		6,030
Permanent Plantings [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	29,242		35,904
Permanent Plantings [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	504,607		524,774
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		0	[1]	0	[4]
Permanent Plantings [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	486,117		503,414
Permanent Plantings [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	12,434		12,150
Permanent Plantings [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	6,056		9,210
Livestock [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,210,417		1,260,618
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		5,075	[1]	5,045	[4]
Livestock [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	1,129,796		1,174,057
Livestock [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	55,939		61,320
Livestock [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	24,682		25,241
Livestock [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	434,929		412,620
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		753	[1]	4,555	[4]
Livestock [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	386,273		375,010
Livestock [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	44,325		31,039
Livestock [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	4,331		6,571
Livestock [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	775,488		847,998
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		4,322	[1]	490	[4]
Livestock [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	743,523		799,047
Livestock [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	11,614		30,281
Livestock [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	20,351		18,670
Part-Time Farm [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	211,565		173,954
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		2,464	[1]	2,828	[4]
Part-Time Farm [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	196,081		154,931
Part-Time Farm [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	1,263		1,963
Part-Time Farm [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	14,221		17,060
Part-Time Farm [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	101,308		69,511
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		2,276	[1]	2,828	[4]
Part-Time Farm [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	92,327		57,239
Part-Time Farm [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	0		612
Part-Time Farm [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	8,981		11,660
Part-Time Farm [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	110,257		104,443
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		188	[1]	0	[4]
Part-Time Farm [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	103,754		97,692
Part-Time Farm [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	1,263		1,351
Part-Time Farm [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	5,240		5,400
Agriculture Storage and Processing [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	91,099		114,360
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		13,500	[1]	0	[4]
Agriculture Storage and Processing [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	77,599		93,366
Agriculture Storage and Processing [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	0		0
Agriculture Storage and Processing [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	13,500		20,994
Agriculture Storage and Processing [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	24,469		29,003
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		0	[1]	0	[4]
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	24,469		29,003
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	0		0
Agriculture Storage and Processing [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	0		0
Agriculture Storage and Processing [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	66,630		85,357
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		13,500	[1]	0	[4]
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	53,130		64,363
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	0		0
Agriculture Storage and Processing [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	13,500		20,994
Other Commodity [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	5,838		6,781
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		0	[1]	0	[4]
Other Commodity [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	5,202		6,117
Other Commodity [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	7		8
Other Commodity [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	629		656
Other Commodity [Member] | On-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	79		0
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		0	[1]	0	[4]
Other Commodity [Member] | On-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	79		0
Other Commodity [Member] | On-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	0		0
Other Commodity [Member] | On-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	0		0
Other Commodity [Member] | Off-balance sheet [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	5,759		6,781
Financing Receivable, Recorded Investment, Equal to Greater than 90 Days Past Due		0	[1]	0	[4]
Other Commodity [Member] | Off-balance sheet [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1]	5,123		6,117
Other Commodity [Member] | Off-balance sheet [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[5]	7		8
Other Commodity [Member] | Off-balance sheet [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Financing Receivable, Gross	[1],[6]	$ 629		$ 656

[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] 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).

[3] Includes loans and loans underlying off-balance sheet Farm & Ranch Guaranteed Securities and LTSPCs that are 90 days or more past due, in foreclosure, or in bankruptcy, excluding loans performing under either their original loan terms or a court-approved bankruptcy plan.

[4] 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.

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

[6] 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.