CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 84,317	$ 77,300	$ 73,839
Adjustments to reconcile net income to net cash provided by operating activities:
Net amortization of deferred gains, premiums, and discounts on loans, investments, Farmer Mac Guaranteed Securities, and USDA Securities	1,739	1,828	2,889
Amortization of debt premiums, discounts and issuance costs	22,858	31,757	15,060
Net change in fair value of trading securities, hedged assets, and financial derivatives	(11,187)	(15,086)	(12,144)
(Gains)/losses on sale of real estate owned	(1,748)	(15)	1
Total provision for losses	1,758	1,002	208
Excess Tax Benefits from Share-Based Compensation	860	0	0
Deferred income taxes	3,221	4,103	3,992
Other Noncash Income (Expense)	11	9	(9)
Stock-based compensation expense	2,702	3,343	3,269
Proceeds from repayment of trading investment securities	0	2,212	657
Proceeds from repayment of loans purchased as held for sale	70,630	70,087	95,592
Net change in:
Interest receivable	(32,468)	(9,922)	(5,826)
Guarantee and commitment fees receivable	94	1,318	(727)
Other assets	3,641	43,560	8,454
Accrued interest payable	25,702	2,079	(734)
Other liabilities	2,881	(884)	377
Net cash provided by operating activities	175,011	212,691	184,898
Cash flows from investing activities:
Payments to Acquire Held-to-maturity Securities	(45,032)	0	0
Purchases of loans held for investment	(1,266,926)	(1,016,515)	(837,176)
Purchases of defaulted loans	(5,981)	(2,516)	(16,907)
Proceeds from repayment of loans purchased as held for investment	435,356	402,897	311,136
Proceeds from sale of Farmer Mac Guaranteed Securities	519,219	609,347	336,913
Proceeds from sale of real estate owned	8,099	295	(1)
Net cash used by investing activities	(1,848,275)	(593,409)	(1,250,533)
Cash flows from financing activities:
Excess tax benefits related to stock-based awards	0	1,428	154
Payments to third parties on debt securities of consolidated trusts	(101,218)	(82,209)	(47,574)
Proceeds from common stock issuance	238	553	1,689
Tax payments related to share-based awards	(2,536)	(4,103)	(543)
Investment in subsidiary - non-controlling interest	0	53	242
Payments for Repurchase of Redeemable Preferred Stock	0	0	(244,000)
Payments of Ordinary Dividends, Noncontrolling Interest	0	0	(5,415)
Dividends paid on common and preferred stock	(28,439)	(24,067)	(20,182)
Net cash provided/(used) by financing activities	1,710,057	(564,137)	912,332
Net increase in cash and cash equivalents	36,793	(944,855)	(153,303)
Cash and cash equivalents at beginning of period	265,229	1,210,084	1,363,387
Cash and cash equivalents at end of period	302,022	265,229	1,210,084
Medium-term Notes [Member]
Cash flows from financing activities:
Proceeds from issuance of discount notes and medium-term notes	8,600,860	6,519,115	4,375,368
Payments to redeem discount notes and medium-term notes	(4,675,300)	(4,083,450)	(4,842,281)
Notes Payable to Banks [Member]
Cash flows from financing activities:
Proceeds from issuance of discount notes and medium-term notes	51,980,890	95,036,368	97,129,959
Payments to redeem discount notes and medium-term notes	(54,064,438)	(97,918,539)	(95,424,765)
Investment Securities [Member]
Cash flows from investing activities:
Purchases of available-for-sale investment securities and Farmer Mac Guaranteed Securities and USDA Guaranteed Securities	(979,671)	(1,753,423)	(2,403,910)
Proceeds from repayment of available-for-sale investment securities, Farmer Mac Guaranteed Securities and USDA Guaranteed Securities	1,326,779	1,725,045	1,489,074
Proceeds from sale of available-for-sale investment securities	10,218	186,769	83,735
Farmer Mac Guaranteed Securities and USDA Securities [Member]
Cash flows from investing activities:
Purchases of available-for-sale investment securities and Farmer Mac Guaranteed Securities and USDA Guaranteed Securities	(2,913,514)	(2,579,980)	(1,180,570)
Proceeds from repayment of available-for-sale investment securities, Farmer Mac Guaranteed Securities and USDA Guaranteed Securities	1,063,178	1,834,672	967,173
Common Class C, Non-Voting [Member]
Cash flows from financing activities:
Common stock repurchased	$ 0	$ (9,286)	$ (10,320)