Loans and Allowance for Losses and Concentrations of Credit Risk - Allowance for Losses by Impairment Method and Commodity (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		$ 6,031,565	$ 5,649,604
Financing Receivable, Individually Evaluated for Impairment		107,739	75,695
Financing Receivable, Gross	[1],[2]	6,139,304	5,725,299
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		5,143	4,713
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		2,292	1,850
Financing Receivable, Allowance for Credit Losses		7,435	6,563	$ 10,127	$ 13,334
Total (release of)/provision for losses		1,002	208	(3,166)
Financing Receivable, Allowance for Credit Losses, Write-downs		(130)	(3,772)	(86)
Crops [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		3,357,301	3,224,911
Financing Receivable, Individually Evaluated for Impairment		53,197	18,740
Financing Receivable, Gross	[1]	3,410,498	3,243,651
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		2,420	2,315
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		945	476
Financing Receivable, Allowance for Credit Losses		3,365	2,791	2,519
Total (release of)/provision for losses		574	272
Financing Receivable, Allowance for Credit Losses, Write-downs		0	0
Permanent Plantings [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		1,006,935	917,127
Financing Receivable, Individually Evaluated for Impairment		30,505	24,284
Financing Receivable, Gross	[1]	1,037,440	941,411
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		933	571
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		790	360
Financing Receivable, Allowance for Credit Losses		1,723	931	2,159
Total (release of)/provision for losses		792	(1,228)
Financing Receivable, Allowance for Credit Losses, Write-downs		0	0
Livestock [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		1,290,332	1,221,983
Financing Receivable, Individually Evaluated for Impairment		15,512	14,798
Financing Receivable, Gross	[1]	1,305,844	1,236,781
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		976	994
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		399	787
Financing Receivable, Allowance for Credit Losses		1,375	1,781	1,423
Total (release of)/provision for losses		(406)	358
Financing Receivable, Allowance for Credit Losses, Write-downs		0	0
Part-Time Farm [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		315,549	203,090
Financing Receivable, Individually Evaluated for Impairment		8,525	8,035
Financing Receivable, Gross	[1]	324,074	211,125
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		247	181
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		158	227
Financing Receivable, Allowance for Credit Losses		405	408	467
Total (release of)/provision for losses		127	52
Financing Receivable, Allowance for Credit Losses, Write-downs		(130)	(111)
Agriculture Storage and Processing [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		48,051	72,152
Financing Receivable, Individually Evaluated for Impairment		0	9,838
Financing Receivable, Gross	[1]	48,051	81,990
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		533	649
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		533	649	3,552
Total (release of)/provision for losses		(116)	758
Financing Receivable, Allowance for Credit Losses, Write-downs		0	(3,661)
Other Commodity [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		13,397	10,341
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Gross	[1]	13,397	10,341
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		34	3
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		34	3	7
Total (release of)/provision for losses		31	(4)
Financing Receivable, Allowance for Credit Losses, Write-downs		0	0
On-balance sheet [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		3,426,768	2,900,868
Financing Receivable, Individually Evaluated for Impairment		87,686	57,107
Financing Receivable, Gross	[1]	3,514,454	2,957,975
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		3,630	3,387
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		1,785	1,093
Financing Receivable, Allowance for Credit Losses		5,415	4,480
On-balance sheet [Member] | Crops [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		2,115,450	1,911,039
Financing Receivable, Individually Evaluated for Impairment		41,648	12,803
Financing Receivable, Gross	[1]	2,157,098	1,923,842
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		2,000	1,968
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		613	290
Financing Receivable, Allowance for Credit Losses		2,613	2,258
On-balance sheet [Member] | Permanent Plantings [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		569,360	433,654
Financing Receivable, Individually Evaluated for Impairment		27,770	21,247
Financing Receivable, Gross	[1]	597,130	454,901
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		652	434
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		770	218
Financing Receivable, Allowance for Credit Losses		1,422	652
On-balance sheet [Member] | Livestock [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		537,859	444,320
Financing Receivable, Individually Evaluated for Impairment		10,658	5,958
Financing Receivable, Gross	[1]	548,517	450,278
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		735	702
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		270	384
Financing Receivable, Allowance for Credit Losses		1,005	1,086
On-balance sheet [Member] | Part-Time Farm [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		183,660	92,712
Financing Receivable, Individually Evaluated for Impairment		7,610	7,261
Financing Receivable, Gross	[1]	191,270	99,973
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		193	116
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		132	201
Financing Receivable, Allowance for Credit Losses		325	317
On-balance sheet [Member] | Agriculture Storage and Processing [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		11,545	15,944
Financing Receivable, Individually Evaluated for Impairment		0	9,838
Financing Receivable, Gross	[1]	11,545	25,782
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		22	167
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		22	167
On-balance sheet [Member] | Other Commodity [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		8,894	3,199
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Gross	[1]	8,894	3,199
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		28	0
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		28	0
Off-balance sheet [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		2,604,797	2,748,736
Financing Receivable, Individually Evaluated for Impairment		20,053	18,588
Financing Receivable, Gross	[1]	2,624,850	2,767,324
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,513	1,326
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		507	757
Financing Receivable, Allowance for Credit Losses		2,020	2,083
Off-balance sheet [Member] | Crops [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		1,241,851	1,313,872
Financing Receivable, Individually Evaluated for Impairment		11,549	5,937
Financing Receivable, Gross	[1]	1,253,400	1,319,809
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		420	347
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		332	186
Financing Receivable, Allowance for Credit Losses		752	533
Off-balance sheet [Member] | Permanent Plantings [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		437,575	483,473
Financing Receivable, Individually Evaluated for Impairment		2,735	3,037
Financing Receivable, Gross	[1]	440,310	486,510
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		281	137
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		20	142
Financing Receivable, Allowance for Credit Losses		301	279
Off-balance sheet [Member] | Livestock [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		752,473	777,663
Financing Receivable, Individually Evaluated for Impairment		4,854	8,840
Financing Receivable, Gross	[1]	757,327	786,503
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		241	292
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		129	403
Financing Receivable, Allowance for Credit Losses		370	695
Off-balance sheet [Member] | Part-Time Farm [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		131,889	110,378
Financing Receivable, Individually Evaluated for Impairment		915	774
Financing Receivable, Gross	[1]	132,804	111,152
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		54	65
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		26	26
Financing Receivable, Allowance for Credit Losses		80	91
Off-balance sheet [Member] | Agriculture Storage and Processing [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		36,506	56,208
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Gross	[1]	36,506	56,208
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		511	482
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		511	482
Off-balance sheet [Member] | Other Commodity [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Collectively Evaluated for Impairment		4,503	7,142
Financing Receivable, Individually Evaluated for Impairment		0	0
Financing Receivable, Gross	[1]	4,503	7,142
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		6	3
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		0	0
Financing Receivable, Allowance for Credit Losses		$ 6	$ 3
Allowance for Loan and Lease Losses [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Financing Receivable, Allowance for Credit Losses, Write-downs				$ (86)

[1] Amounts represent unpaid principal balance of risk-rated loans, which is the basis Farmer Mac uses to analyze its portfolio, and recorded investment of past due loans.

[2] Geographic regions: Northwest (AK, ID, MT, OR, WA, WY); Southwest (AZ, CA, CO, HI, NM, NV, UT); Mid-North (IA, IL, IN, MI, MN, NE, ND, SD, WI); Mid-South (AR, KS, LA, MO, OK, TX); Northeast (CT, DE, KY, MA, MD, ME, NH, NJ, NY, OH, PA, RI, VA, VT, WV); Southeast (AL, FL, GA, MS, NC, SC, TN).