CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Class C, Non-Voting [Member]	Series D Preferred Stock [Member]	Series B Preferred Stock [Member]	Preferred Stock [Member]	Preferred Stock [Member] Series D Preferred Stock [Member]	Preferred Stock [Member] Series B Preferred Stock [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]	Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect from change in hedge accounting	$ 498											$ 27	$ 471
Adjusted Beginning Balance	708,644				$ 204,759			$ 10,619		$ 118,979		51,112	323,175
Beginning balance ( in shares) at Dec. 31, 2017					8,400			10,619
Beginning balance at Dec. 31, 2017	708,146				$ 204,759			$ 10,619		118,979		51,085	322,704
Net income:
Net income attributable to Farmer Mac	25,819												25,819
Other comprehensive loss, net of tax	20,999											20,999
Preferred stock	(3,295)												(3,295)
Common stock	(6,161)												(6,161)
Issuance of stock (in shares)									31
Issuance of stock		$ 34							$ 31		$ 3
Stock-based compensation cost	664									664
Other stock-based award activity	(1,438)									(1,438)
Ending balance (in shares) at Mar. 31, 2018					8,400			10,650
Ending balance at Mar. 31, 2018	745,266				$ 204,759			$ 10,650		118,208		72,111	339,538
Beginning balance ( in shares) at Dec. 31, 2017					8,400			10,619
Beginning balance at Dec. 31, 2017	708,146				$ 204,759			$ 10,619		118,979		51,085	322,704
Net income:
Net income attributable to Farmer Mac	85,224
Other comprehensive loss, net of tax	12,889
Loss on retirement of preferred stock	0
Ending balance (in shares) at Sep. 30, 2018					8,400			10,669
Ending balance at Sep. 30, 2018	777,591				$ 204,759			$ 10,669		118,183		64,001	379,979
Beginning balance ( in shares) at Mar. 31, 2018					8,400			10,650
Beginning balance at Mar. 31, 2018	745,266				$ 204,759			$ 10,650		118,208		72,111	339,538
Net income:
Net income attributable to Farmer Mac	29,636												29,636
Other comprehensive loss, net of tax	1,299											1,299
Preferred stock	(3,296)												(3,296)
Common stock	(6,186)												(6,186)
Issuance of stock (in shares)									17
Issuance of stock		21							$ 17		4
Stock-based compensation cost	605									605
Other stock-based award activity	(1,133)									(1,133)
Ending balance (in shares) at Jun. 30, 2018					8,400			10,667
Ending balance at Jun. 30, 2018	766,212				$ 204,759			$ 10,667		117,684		73,410	359,692
Net income:
Net income attributable to Farmer Mac	29,769												29,769
Other comprehensive loss, net of tax	(9,409)											(9,409)
Preferred stock	(3,295)												(3,295)
Common stock	(6,187)												(6,187)
Issuance of stock (in shares)									2
Issuance of stock		2							$ 2
Loss on retirement of preferred stock	0
Stock-based compensation cost	613									613
Other stock-based award activity	(114)									(114)
Ending balance (in shares) at Sep. 30, 2018					8,400			10,669
Ending balance at Sep. 30, 2018	777,591				$ 204,759			$ 10,669		118,183		64,001	379,979
Beginning balance ( in shares) at Dec. 31, 2018					8,400			10,669
Beginning balance at Dec. 31, 2018	752,557				$ 204,759			$ 10,669		118,822		24,956	393,351
Net income:
Net income attributable to Farmer Mac	25,170												25,170
Other comprehensive loss, net of tax	(3,702)											(3,702)
Preferred stock	(3,296)												(3,296)
Common stock	(7,470)												(7,470)
Issuance of stock (in shares)									20
Issuance of stock		23							$ 20		3
Stock-based compensation cost	724									724
Other stock-based award activity	(708)									(708)
Ending balance (in shares) at Mar. 31, 2019					8,400			10,689
Ending balance at Mar. 31, 2019	763,298				$ 204,759			$ 10,689		118,841		21,254	407,755
Beginning balance ( in shares) at Dec. 31, 2018					8,400			10,669
Beginning balance at Dec. 31, 2018	752,557				$ 204,759			$ 10,669		118,822		24,956	393,351
Net income:
Net income attributable to Farmer Mac	77,048
Other comprehensive loss, net of tax	(67,980)
Loss on retirement of preferred stock	(1,956)
Ending balance (in shares) at Sep. 30, 2019					9,400			10,710
Ending balance at Sep. 30, 2019	750,259				$ 228,374			$ 10,710		118,720		(43,024)	435,479
Beginning balance ( in shares) at Mar. 31, 2019					8,400			10,689
Beginning balance at Mar. 31, 2019	763,298				$ 204,759			$ 10,689		118,841		21,254	407,755
Net income:
Net income attributable to Farmer Mac	34,045												34,045
Other comprehensive loss, net of tax	(34,097)											(34,097)
Preferred stock	(3,785)												(3,785)
Common stock	(7,490)												(7,490)
Issuance of stock (in shares)						4,000			11
Issuance of stock		14	$ 96,659			$ 96,659			$ 11		3
Redemption of Series B preferred stock (in shares)							(3,000)
Redemption of Series B preferred stock				$ (73,044)			$ (73,044)
Loss on retirement of preferred stock	(1,956)												(1,956)
Stock-based compensation cost	533									533
Other stock-based award activity	(435)									(435)
Ending balance (in shares) at Jun. 30, 2019					9,400			10,700
Ending balance at Jun. 30, 2019	773,742				$ 228,374			$ 10,700		118,942		(12,843)	428,569
Net income:
Net income attributable to Farmer Mac	17,833												17,833
Other comprehensive loss, net of tax	(30,181)											(30,181)
Preferred stock	(3,427)												(3,427)
Common stock	(7,496)												(7,496)
Issuance of stock (in shares)									10
Issuance of stock		$ 29							$ 10		$ 19
Loss on retirement of preferred stock	0
Stock-based compensation cost	407									407
Other stock-based award activity	(648)									(648)
Ending balance (in shares) at Sep. 30, 2019					9,400			10,710
Ending balance at Sep. 30, 2019	$ 750,259				$ 228,374			$ 10,710		$ 118,720		$ (43,024)	$ 435,479