CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	$ 582,500	$ 678,975	$ 781,829
Net income attributable to Farmer Mac	13,260	1,765
Balance, end of period	582,500	678,975	781,829
Other comprehensive income, net of tax	35,651	31,156
Cash dividends:
Loss on retirement of preferred stock	(8,147)	0
Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period (Shares)	8,400	5,400	8,400	2,400
Balance, beginning of period	204,759	131,639	204,759	58,333
Balance, end of period	204,759	131,639	204,759	58,333
Balance, end of period (Shares)	8,400	5,400	8,400	2,400
Preferred Stock [Member] | Series B Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Series preferred stock (Shares)	0	3,000
Issuance of Series preferred stock	0	73,306
Issuance of Class C common stock (Shares)	0	3,000
Issuance of Class C common stock	0	73,306
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period (Shares)	10,937	10,886	10,937	10,886
Balance, beginning of period	10,937	10,886	10,937	10,886
Balance, end of period	10,937	10,886	10,937	10,886
Balance, end of period (Shares)	10,937	10,886	10,937	10,886
Additional Paid-in Capital [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	114,364	111,477	113,559	110,722
Issuance of Series preferred stock	4	6
Issuance of Class C common stock	4	6
Stock-based compensation expense	839	713
Tax effect of stock-based awards	(38)	36
Balance, end of period	114,364	111,477	113,559	110,722
Retained Earnings [Member}
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	201,081	168,166	201,013	168,877
Net income attributable to Farmer Mac	13,260	1,765
Balance, end of period	201,081	168,166	201,013	168,877
Cash dividends:
Common stock ($0.16 per share in 2015, $0.14 per share in 2014)	(1,750)	(1,524)
Retained Earnings [Member} | Series A Preferred Stock [Member]
Cash dividends:
Preferred Stock Series A ($0.3672 per share in 2015 and 2014) Preferred stock, Series B ($0.4297 per share in 2015 and $0.105 per share in 2014), Preferred stock Series C ($0.3750 per share)	(881)	(881)
Retained Earnings [Member} | Series B Preferred Stock [Member]
Cash dividends:
Preferred Stock Series A ($0.3672 per share in 2015 and 2014) Preferred stock, Series B ($0.4297 per share in 2015 and $0.105 per share in 2014), Preferred stock Series C ($0.3750 per share)	(1,289)	(71)
Retained Earnings [Member} | Series C Preferred Stock [Member]
Cash dividends:
Preferred Stock Series A ($0.3672 per share in 2015 and 2014) Preferred stock, Series B ($0.4297 per share in 2015 and $0.105 per share in 2014), Preferred stock Series C ($0.3750 per share)	(1,125)	0
Accumulated Other Comprehensive Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	51,184	14,954	15,533	(16,202)
Balance, end of period	51,184	14,954	15,533	(16,202)
Other comprehensive income, net of tax	35,651	31,156
Total Stockholders Equity [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	582,325	437,122
Balance, end of period	582,325	437,122
Non-controlling Interest - Preferred Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period	175	241,853	236,028	241,853
Balance, end of period	175	241,853	236,028	241,853
Redemption of preferred stock, Farmer Mac II LLC	$ (235,853)	$ 0