Loans and Allowance for Losses and Concentrations of Credit Risk - Impaired Financing Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	$ 23,607		$ 22,291
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	23,562		21,840
Impaired Financing Receivable, with Related Allowance, Recorded Investment	52,115	[1]	61,772	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	52,133		60,597
Impaired Financing Receivable, Recorded Investment	75,722		84,063
Impaired Financing Receivable, Unpaid Principal Balance	75,695		82,437
Impaired Financing Receivable, Related Allowance	1,850		2,637
Financing Receivable, Recorded Investment, Nonaccrual Status	41,672	[3]	30,152	[4]
Impaired Financing Receivable, Average Recorded Investment	90,691		90,009
Impaired Financing Receivable, Interest Income, Cash Basis Method	1,514		1,533
Crops [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,772		4,877
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	3,720		4,723
Impaired Financing Receivable, with Related Allowance, Recorded Investment	15,103	[1]	10,753	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	15,020		10,042
Impaired Financing Receivable, Recorded Investment	18,875		15,630
Impaired Financing Receivable, Unpaid Principal Balance	18,740		14,765
Impaired Financing Receivable, Related Allowance	476		397
Financing Receivable, Recorded Investment, Nonaccrual Status	5,105	[3]	5,168	[4]
Impaired Financing Receivable, Average Recorded Investment	22,315		20,625
Impaired Financing Receivable, Interest Income, Cash Basis Method	381		373
Permanent Plantings [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	12,340		5,837
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	12,346		5,750
Impaired Financing Receivable, with Related Allowance, Recorded Investment	11,939	[1]	33,690	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	11,938		33,393
Impaired Financing Receivable, Recorded Investment	24,279		39,527
Impaired Financing Receivable, Unpaid Principal Balance	24,284		39,143
Impaired Financing Receivable, Related Allowance	360		1,515
Financing Receivable, Recorded Investment, Nonaccrual Status	16,546	[3]	14,413	[4]
Impaired Financing Receivable, Average Recorded Investment	36,326		43,221
Impaired Financing Receivable, Interest Income, Cash Basis Method	472		474
Livestock [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5,644		9,576
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	5,645		9,386
Impaired Financing Receivable, with Related Allowance, Recorded Investment	9,050	[1]	5,979	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	9,153		5,897
Impaired Financing Receivable, Recorded Investment	14,694		15,555
Impaired Financing Receivable, Unpaid Principal Balance	14,798		15,283
Impaired Financing Receivable, Related Allowance	787		361
Financing Receivable, Recorded Investment, Nonaccrual Status	4,313	[3]	4,438	[4]
Impaired Financing Receivable, Average Recorded Investment	14,077		13,543
Impaired Financing Receivable, Interest Income, Cash Basis Method	353		327
Part-Time Farm [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	1,851		2,001
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,851		1,981
Impaired Financing Receivable, with Related Allowance, Recorded Investment	6,185	[1]	11,350	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	6,184		11,265
Impaired Financing Receivable, Recorded Investment	8,036		13,351
Impaired Financing Receivable, Unpaid Principal Balance	8,035		13,246
Impaired Financing Receivable, Related Allowance	227		364
Financing Receivable, Recorded Investment, Nonaccrual Status	5,870	[3]	6,133	[4]
Impaired Financing Receivable, Average Recorded Investment	10,605		12,596
Impaired Financing Receivable, Interest Income, Cash Basis Method	308		359
Agriculture Storage and Processing [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0		0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	0		0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	9,838	[1]	0	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	9,838		0
Impaired Financing Receivable, Recorded Investment	9,838		0
Impaired Financing Receivable, Unpaid Principal Balance	9,838		0
Impaired Financing Receivable, Related Allowance	0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	9,838	[3]	0	[4]
Impaired Financing Receivable, Average Recorded Investment	7,368		0
Impaired Financing Receivable, Interest Income, Cash Basis Method	0		0
Other Commodity [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	0		0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	0		0
Impaired Financing Receivable, with Related Allowance, Recorded Investment	0	[1]	0	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0		0
Impaired Financing Receivable, Recorded Investment	0		0
Impaired Financing Receivable, Unpaid Principal Balance	0		0
Impaired Financing Receivable, Related Allowance	0		0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	[3]	0	[4]
Impaired Financing Receivable, Average Recorded Investment	0		24
Impaired Financing Receivable, Interest Income, Cash Basis Method	0		0
Collateral Dependent Not Individually Analyzed [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Recorded Investment	46,400		54,400
Impaired Financing Receivable, Related Allowance	$ 1,000		$ 1,200
Impaired Financing Receivable, Impairment analysis performed percent	61.00%		65.00%
Less than 90 days past due [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 14,700	[3]	$ 11,700	[4]

[1] Impairment analysis was performed in the aggregate in consideration of similar risk characteristics of the assets and historical statistics on $46.4 million (61 percent) of impaired loans as of December 31, 2015, which resulted in a specific reserve of $1.0 million.

[2] Impairment analysis was performed in the aggregate in consideration of similar risk characteristics of the assets and historical statistics on $54.4 million (65 percent) of impaired loans as of December 31, 2014, which resulted in a specific reserve of $1.2 million.

[3] Includes $14.7 million of loans that are less than 90 days delinquent but which have not met Farmer Mac's performance criteria for returning to accrual status.

[4] Includes $11.7 million of loans that are less than 90 days delinquent but which have not met Farmer Mac's performance criteria for returning to accrual status.