Fair Value Disclosures - Summary of Carrying Value and Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 752,502	$ 817,046
Loans	2,577,741	2,971,187
Financial derivatives, Assets	36,894	40,250
Notes payable - Due within one year	6,482,643	6,091,573
Notes payable - Due after one year	4,706,115	4,288,670
Debt securities of consolidated trusts held by third parties	186,253	726,826
Financial derivatives, Liabilities	162,591	160,024
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	752,502	817,046
Loans	2,540,902	2,894,156
Financial derivatives, Assets	36,894	40,250
Notes payable - Due within one year	6,482,817	6,087,879
Notes payable - Due after one year	4,519,192	4,104,882
Debt securities of consolidated trusts held by third parties	184,499	701,583
Financial derivatives, Liabilities	162,591	160,024
Investment Securities | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	2,496,451	2,184,490
Investment Securities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	2,496,451	2,184,490
Farmer Mac Guaranteed Securities | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	22,165	17,960
Farmer Mac Guaranteed Securities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	20,604	15,498
LTSPCs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	22,761	22,802
LTSPCs | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	17,518	15,886
LTSPCs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment obligations	21,957	22,047
LTSPCs | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment obligations	16,714	15,131
Farmer Mac Guaranteed Securities | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment obligations	18,897	14,771
Farmer Mac Guaranteed Securities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment obligations	17,337	12,309
Farmer Mac Guarantee | Farmer Mac Guaranteed Securities | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	4,444,467	4,289,272
Farmer Mac Guarantee | Farmer Mac Guaranteed Securities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	4,444,467	4,289,272
USDA Guarantee | USDA Guaranteed Securities | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	1,565,463	1,491,905
USDA Guarantee | USDA Guaranteed Securities | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	$ 1,565,463	$ 1,491,905