Business Segment Reporting - Narrative (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total notes payable	$ 13,645,905	$ 12,825,139
Farmer Mac II LLC [Member]
Segment Reporting Information [Line Items]
Assets, Fair Value Disclosure	1,900,000
Total notes payable	777,000
Common Stock outstanding	$ 1,000,000