Accounting Policies - Supplemental Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011
cash paid during the period for: [Abstract]
Interest			$ 90,588	$ 78,598
Income taxes			16,500	20,568
Non-cash activity:
Real estate owned acquired through loan liquidation			1,130	2,723
Loans acquired and securitized as Farmer Mac Guaranteed Securities			24,008	10,656
Consolidation of Farmer Mac I Guaranteed Securities from off-balance sheet to loans held for investment in consolidated trusts and to debt securities of consolidated trusts held by third parties			24,008	10,656
Deconsolidation of loans held for investment in consolidated trusts and debt securities of consolidated trusts held by third parties - transferred to off-balance sheet Farmer Mac I Guaranteed Securities	460,300	460,300	460,261	0
Transfers of loans held for sale to loans held for investment			$ 0	$ 878,798