Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Farmer Mac Guaranteed Securities and USDA Securities (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014		Oct. 01, 2016	Jan. 02, 2014
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Transfer of USDA Guaranteed Securities- Available-for-sale to Held-to-maturity; Unrealized holding gains										$ 73,100
Trading Securities [Abstract]
Transfer of Farmer Mac Guaranteed Securities - Available-for-sale to Held-to-maturity; Unrealized holding gains										700	$ 22,300
Transfer of Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Available-for-sale to Held-to-maturity; Unrealized holding gains										$ 73,800
Farmer Mac Guaranteed Securities and USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	$ 71,952				$ 71,952
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	3,086,504				3,086,504
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	3,158,456				3,158,456
Held to Maturity; Unrealized Holding Gains	7,192				7,192
Held to Maturity - Unrealized Holding Loss	(99,004)				(99,004)
Held-to-maturity Securities, Fair Value	3,066,644				3,066,644
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance		$ 6,045,828					$ 6,045,828
Available-for-sale Securities, Amortized Cost Basis	4,888,904	6,047,385			4,888,904		6,047,385
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		64,131					64,131
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		70,567					70,567
Available-for-sale, at fair value	4,853,685	6,040,949			4,853,685		6,040,949
Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	(1,833)				(1,833)
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	1,151,064				1,151,064
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,149,231				1,149,231
Held to Maturity; Unrealized Holding Gains	7,192				7,192
Held to Maturity - Unrealized Holding Loss	(3,414)				(3,414)
Held-to-maturity Securities, Fair Value	1,153,009				1,153,009
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance		4,196,506					4,196,506
Available-for-sale Securities, Amortized Cost Basis		4,196,173					4,196,173
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		26,971					26,971
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		70,539					70,539
Available-for-sale, at fair value		4,152,605					4,152,605
USDA Securities [Member]
Available-for-sale Securities [Abstract]
Available-for-sale, at fair value	0	1,888,344			0		1,888,344
Trading Securities [Abstract]
Trading, at fair value	20,388	28,975			20,388		28,975
Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities and USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)		1,557					1,557
Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)		(333)					(333)
Institutional Credit [Member] | Farmer Mac Guaranteed Securities [Member]
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	1,115,465	1,274,431			1,115,465		1,274,431
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,113,189	1,274,016			1,113,189		1,274,016
Held to Maturity; Unrealized Holding Gains	7,187	7,801			7,187		7,801
Held to Maturity - Unrealized Holding Loss	(3,175)	0			(3,175)		0
Held-to-maturity Securities, Fair Value	1,117,201	1,281,817			1,117,201		1,281,817
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	4,889,007	4,164,952			4,889,007		4,164,952
Available-for-sale Securities, Amortized Cost Basis	4,888,904	4,164,952			4,888,904		4,164,952
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	28,715	26,831			28,715		26,831
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	63,934	70,539			63,934		70,539
Available-for-sale, at fair value	4,853,685	4,121,244			4,853,685		4,121,244
Institutional Credit [Member] | Held-to-maturity Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	(2,276)	(415)			(2,276)		(415)
Institutional Credit [Member] | Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	(103)	0			(103)		0
USDA Guarantees [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	400	(200)			400		(200)
USDA Guarantees [Member] | Farmer Mac Guaranteed Securities [Member]
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	35,599				35,599
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	36,042				36,042
Held to Maturity; Unrealized Holding Gains	5				5
Held to Maturity - Unrealized Holding Loss	(239)				(239)
Held-to-maturity Securities, Fair Value	35,808				35,808
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance		31,554					31,554
Available-for-sale Securities, Amortized Cost Basis		31,221					31,221
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		140					140
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		0					0
Available-for-sale, at fair value		31,361					31,361
USDA Guarantees [Member] | USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	73,785				73,785
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	1,935,440				1,935,440
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	2,009,225				2,009,225
Held to Maturity; Unrealized Holding Gains	0				0
Held to Maturity - Unrealized Holding Loss	(95,590)				(95,590)
Held-to-maturity Securities, Fair Value	1,913,635				1,913,635
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance		1,849,322					1,849,322
Available-for-sale Securities, Amortized Cost Basis		1,851,212					1,851,212
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		37,160					37,160
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax		28					28
Available-for-sale, at fair value		1,888,344					1,888,344
Trading Securities [Abstract]
Trading Securities Unpaid Principal Balance	19,360	27,129			19,360		27,129
Trading Securities, Debt, Amortized Cost	20,737	29,063			20,737		29,063
Trading Securities, Unrealized Gains	41	125
Trading Securities, Unrealized Holding Loss	390	213
Trading, at fair value	20,388	28,975			20,388		28,975
USDA Guarantees [Member] | Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	443	(333)			443		(333)
USDA Guarantees [Member] | Available-for-sale Securities [Member] | USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)		1,890					1,890
USDA Guarantees [Member] | Trading Securities [Member] | USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	$ 1,377	$ 1,934			1,377		1,934
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					2,013,151			$ 1,632,786
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Farmer Mac Guaranteed Securities [Member] | Available-for-sale Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					32,824		$ 0	1,632,786
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Farmer Mac Guaranteed Securities [Member] | USDA Guarantee [Member] | Available-for-sale Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					2,000,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Farmer Mac Guaranteed Securities [Member] | Farmer Mac Guaranteed Securities [Member] | Available-for-sale Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					32,800
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Farmer Mac Guaranteed Securities [Member] | Institutional Credit [Member] | Available-for-sale Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3			$ 0	$ 1,600,000	0			1,632,786	[1]
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Farmer Mac Guaranteed Securities [Member] | USDA Guarantees [Member] | Available-for-sale Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3					$ 32,824	[2]		$ 0

[1] Includes $1.6 billion of AgVantage securities transferred from available-for-sale to held-to-maturity on January 1, 2014 and $20.7 million of AgVantage securities purchased during 2014 transferred from available-for-sale to held-to-maturity.

[2] Includes $32.8 million of Farmer Mac Guaranteed USDA Securities and $2.0 billion of USDA Securities transferred from available-for-sale to held-to-maturity on October 1, 2016.