Loans and Allowance for Losses and Concentrations of Credit Risk - Allowance for Credit Losses Roll Forward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loan Losses	$ 7,410		$ 6,866
Reserve for losses	6,569		6,468
Total Allowance for Losses	13,979	14,252	13,334	16,890
Provision for loan losses	(573)	(430)
Provision for losses	101	746
Total provision for losses	674	1,176
Total Allowance for Losses - Charge-offs	(29)	(3,814)
Eligible Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loan Losses	7,410	7,967	6,866	11,351
Provision for loan losses	(573)	(430)
Allowance for Loan Losses - Charge-offs	(29)	(3,814)
Long-Term Standby Purchase Commitments and Farmer Mac Guaranteed Securities [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserve for losses	6,569	6,285	6,468	5,539
Provision for losses	101	746
Reserve for Losses - Charge-offs	0	0
Agriculture Storage and Processing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	7,715	6,971	7,292	9,661
Total provision for losses	423	935
Total Allowance for Losses - Charge-offs	0	(3,625)
Agriculture Storage and Processing [Member] | Eligible Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Loan Losses - Charge-offs		(3,600)
Crops [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	2,278	2,617	2,124	2,589
Total provision for losses	154	28
Total Allowance for Losses - Charge-offs	0	0
Permanent Plantings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	2,131	2,326	2,186	2,316
Total provision for losses	(55)	199
Total Allowance for Losses - Charge-offs	0	(189)
Livestock [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	1,387	1,587	1,271	1,534
Total provision for losses	116	53
Total Allowance for Losses - Charge-offs	0	0
Part-Time Farm [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	464	733	454	784
Total provision for losses	39	(51)
Total Allowance for Losses - Charge-offs	(29)	0
Other Commodity [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for Losses	4	18	7	6
Total provision for losses	(3)	12
Total Allowance for Losses - Charge-offs	$ 0	$ 0