Loans and Allowance for Losses and Concentrations of Credit Risk - Impaired Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016		Mar. 31, 2015	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	$ 23,706			$ 23,607
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	22,162			23,562
Impaired Financing Receivable, with Related Allowance, Recorded Investment	54,586	[1]		52,115	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	54,030			52,133
Impaired Financing Receivable, Recorded Investment	78,292			75,722
Impaired Financing Receivable, Unpaid Principal Balance	76,192			75,695
Impaired Financing Receivable, Related Allowance	2,035			1,850
Financing Receivable, Recorded Investment, Nonaccrual Status	31,340	[3]		41,672	[4]
Impaired Financing Receivable, Average Recorded Investment	77,007		$ 87,800
Impaired Financing Receivable, Interest Income, Cash Basis Method	133		571
Crops [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	3,982			3,772
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	3,540			3,720
Impaired Financing Receivable, with Related Allowance, Recorded Investment	24,255	[1]		15,103	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	23,787			15,020
Impaired Financing Receivable, Recorded Investment	28,237			18,875
Impaired Financing Receivable, Unpaid Principal Balance	27,327			18,740
Impaired Financing Receivable, Related Allowance	644			476
Financing Receivable, Recorded Investment, Nonaccrual Status	5,514	[3]		5,105	[4]
Impaired Financing Receivable, Average Recorded Investment	23,555		19,218
Impaired Financing Receivable, Interest Income, Cash Basis Method	2		282
Permanent Plantings [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	12,556			12,340
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	12,463			12,346
Impaired Financing Receivable, with Related Allowance, Recorded Investment	10,460	[1]		11,939	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	10,404			11,938
Impaired Financing Receivable, Recorded Investment	23,016			24,279
Impaired Financing Receivable, Unpaid Principal Balance	22,867			24,284
Impaired Financing Receivable, Related Allowance	311			360
Financing Receivable, Recorded Investment, Nonaccrual Status	15,331	[3]		16,546	[4]
Impaired Financing Receivable, Average Recorded Investment	23,648		40,764
Impaired Financing Receivable, Interest Income, Cash Basis Method	44		83
Livestock [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	5,042			5,644
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	4,327			5,645
Impaired Financing Receivable, with Related Allowance, Recorded Investment	12,900	[1]		9,050	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	12,916			9,153
Impaired Financing Receivable, Recorded Investment	17,942			14,694
Impaired Financing Receivable, Unpaid Principal Balance	17,243			14,798
Impaired Financing Receivable, Related Allowance	840			787
Financing Receivable, Recorded Investment, Nonaccrual Status	4,510	[3]		4,313	[4]
Impaired Financing Receivable, Average Recorded Investment	16,318		15,311
Impaired Financing Receivable, Interest Income, Cash Basis Method	15		148
Part-Time Farm [Member]
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	2,126			1,851
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	1,832			1,851
Impaired Financing Receivable, with Related Allowance, Recorded Investment	6,971	[1]		6,185	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	6,923			6,184
Impaired Financing Receivable, Recorded Investment	9,097			8,036
Impaired Financing Receivable, Unpaid Principal Balance	8,755			8,035
Impaired Financing Receivable, Related Allowance	240			227
Financing Receivable, Recorded Investment, Nonaccrual Status	5,985	[3]		5,870	[4]
Impaired Financing Receivable, Average Recorded Investment	8,567		12,507
Impaired Financing Receivable, Interest Income, Cash Basis Method	72		58
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	0	[1]		9,838	[2]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	0			9,838
Impaired Financing Receivable, Recorded Investment	0			9,838
Impaired Financing Receivable, Unpaid Principal Balance	0			9,838
Impaired Financing Receivable, Related Allowance	0			0
Financing Receivable, Recorded Investment, Nonaccrual Status	0	[3]		9,838	[4]
Impaired Financing Receivable, Average Recorded Investment	4,919		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		0
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	48,800			46,400
Impaired Financing Receivable, Related Allowance	$ 1,100			$ 1,000
Impaired Financing Receivable, Impairment analysis performed percent	62.00%			61.00%
Less than 90 days past due [Member]
Financing Receivable, Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status	$ 2,200	[3]		$ 14,700	[4]

[1] Impairment analysis was performed in the aggregate in consideration of similar risk characteristics of the assets and historical statistics on $48.8 million (62 percent) of impaired loans as of March 31, 2016, which resulted in a specific reserve of $1.1 million.

[2] 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.

[3] Includes $2.2 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 $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.