CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Class C, Non-Voting [Member]	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]
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:
Attributable to Farmer Mac	25,819								25,819
Other comprehensive income (loss), net of tax	20,999							20,999
Preferred stock	(3,295)								(3,295)
Common stock	(6,161)								(6,161)
Issuance of Class C Common Stock (in shares)					31
Issuance of Class C Common 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, 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:
Attributable to Farmer Mac	25,170								25,170
Other comprehensive income (loss), net of tax	(3,702)							(3,702)
Preferred stock	(3,296)								(3,296)
Common stock	(7,470)								(7,470)
Issuance of Class C Common Stock (in shares)					20
Issuance of Class C Common 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