CONSOLIDATED STATEMENTS OF EQUITY Statement - USD ($) $ in Thousands	Total	Common Class C, Non-Voting [Member]	Preferred Stock [Member]	Preferred Stock [Member] Common Class C, Non-Voting [Member]	Common Stock [Member]	Common Stock [Member] Common Class C, Non-Voting [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Common Class C, Non-Voting [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Other Comprehensive Income (Loss) [Member] Common Class C, Non-Voting [Member]	Retained Earnings [Member]	Retained Earnings [Member] Common Class C, Non-Voting [Member]	Noncontrolling Interest [Member]	Noncontrolling Interest [Member] Common Class C, Non-Voting [Member]
Beginning Balance (Shares Outstanding) at Dec. 31, 2014			8,400,000		10,937,000
Beginning Balance at Dec. 31, 2014	$ 781,829		$ 204,759		$ 10,937		$ 113,559		$ 15,533		$ 201,013		$ 236,028
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Attributable to Farmer Mac	68,700		0		0		0		0		68,700		0
Less: Net loss/(income) attributable to non-controlling interest	(5,139)		0		0		0		0		0		(214)
Other comprehensive income, net of tax	(26,552)		0		0		0		(26,552)		0		0
Preferred stock	(13,182)		0		0		0		0		(13,182)		0
Common stock	(7,000)		0		0		0		0		(7,000)		0
Stock Issued During Period, Shares, New Issues				0		112,000
Stock Issued During Period, Value, New Issues		$ 1,732		$ 0		$ 112		$ 1,620		$ 0		$ 0		$ 0
Repurchase of Class C Common Stock				0		(362,000)
Repurchase of Class C Common Stock		(10,518)		$ 0		$ (362)		0		0		(10,156)		0
Stock-based compensation cost	3,269		0		0		3,269		0		0		0
Other stock-based award activity	(586)		0		0		(586)		0		0		0
Redemption of interest in subsidiary	242		$ 0		$ 0		0		0		0		242
Ending Balance (Shares Outstanding) at Dec. 31, 2015			8,400,000		10,687,000
Ending Balance at Dec. 31, 2015	553,720		$ 204,759		$ 10,687		117,862		(11,019)		231,228		203
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(244,000)		0		0		0		0		(8,147)		(235,853)
Attributable to Farmer Mac	77,334		0		0		0		0		77,334		0
Less: Net loss/(income) attributable to non-controlling interest	34		0		0		0		0		0		(34)
Other comprehensive income, net of tax	44,777		0		0		0		44,777		0		0
Preferred stock	(13,182)		0		0		0		0		(13,182)		0
Common stock	(10,885)		0		0		0		0		(10,885)		0
Stock Issued During Period, Shares, New Issues				0		159,000
Stock Issued During Period, Value, New Issues		693		$ 0		$ 159		534		0		0		0
Repurchase of Class C Common Stock				0		(307,000)
Repurchase of Class C Common Stock		(9,088)		$ 0		$ (307)		0		0		(8,781)		0
Stock-based compensation cost	3,343		0		0		3,343		0		0		0
Other stock-based award activity	(3,084)		0		0		(3,084)		0		0		0
Redemption of interest in subsidiary	53		$ 0		$ 0		0		0		0		53
Ending Balance (Shares Outstanding) at Dec. 31, 2016			8,400,000		10,539,000
Ending Balance at Dec. 31, 2016	643,647		$ 204,759		$ 10,539		118,655		33,758		275,714		222
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Attributable to Farmer Mac	84,482		0		0		0		0		84,482		0
Less: Net loss/(income) attributable to non-controlling interest	165		0		0		0		0		0		(165)
Other comprehensive income, net of tax	8,274		0		0		0		8,274		0		0
Reclass of Stranded Tax Effects from AOCI to Retained Earnings	0		0		0		0		9,053		(9,053)		0
Preferred stock	(13,182)		0		0		0		0		(13,182)		0
Common stock	(15,257)		0		0		0		0		(15,257)		0
Stock Issued During Period, Shares, New Issues				0		80,000
Stock Issued During Period, Value, New Issues		$ 311		$ 0		$ 80		$ 231		$ 0		$ 0		$ 0
Repurchase of Class C Common Stock		(668,000)
Stock-based compensation cost	2,701		0		0		2,701		0		0		0
Other stock-based award activity	(2,608)		0		0		(2,608)		0		0		0
Redemption of interest in subsidiary	(57)		$ 0		$ 0		0		0		0		(57)
Ending Balance (Shares Outstanding) at Dec. 31, 2017			8,400,000		10,619,000
Ending Balance at Dec. 31, 2017	$ 708,146		$ 204,759		$ 10,619		$ 118,979		$ 51,085		$ 322,704		$ 0