Financial Derivatives - Schedule of Net Income/(Expense) Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Investments and cash equivalents	$ 11,200	$ 4,457	$ 16,916	$ 9,986
Interest Income Farmer Mac Guaranteed Securities and USDA Securities	57,104	42,414	96,361	84,818
Interest Income Loans	76,632	60,214	143,879	119,708
Total interest expense	(75,534)	(51,956)	(125,879)	(106,132)
Gains/(losses) on financial derivatives	3,418	(3,066)	19,492	1,227
Total	72,820	52,063	150,769	109,607
Expense recognized on cash flow hedges	7,302	526	27,793	9,363
Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(194,709)	114,935	(330,874)	(169,112)
Gains/(losses) on fair value hedging relationships	6,037	(1,725)	8,403	(1,379)
Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	(15)	(8)	(29)	(15)
Interest settlements reclassified from AOCI into net income on derivatives	(1,155)	(1,776)	(3,166)	(3,523)
Recognized on hedged items	(1,821)	(643)	(2,608)	(1,298)
Expense recognized on cash flow hedges	(2,991)	(2,427)	(5,803)	(4,836)
Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	27,876	30,126	56,864	60,581
Premium/discount amortization recognized on hedged items	(827)	(257)	(1,681)	(478)
No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	3,418	(3,066)	19,492	1,227
Interest Income Investments and Cash Equivalents | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(22,969)	188	(55,694)	188
Gains/(losses) on fair value hedging relationships	1,169	12	1,868	12
Interest Income Investments and Cash Equivalents | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Recognized on hedged items	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Income Investments and Cash Equivalents | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	3,219	67	5,816	67
Premium/discount amortization recognized on hedged items	(343)	0	(757)	0
Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(149,266)	49,878	(359,914)	(118,922)
Gains/(losses) on fair value hedging relationships	4,404	1,198	3,944	474
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Recognized on hedged items	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	34,431	30,565	66,359	61,341
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Interest Income Loans | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(107,347)	63,978	(236,953)	(80,770)
Gains/(losses) on fair value hedging relationships	2,072	(1,169)	4,398	(146)
Interest Income Loans | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Recognized on hedged items	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Income Loans | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	13,669	11,635	26,288	23,122
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Total Interest Expense | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	84,873	891	321,687	30,392
Gains/(losses) on fair value hedging relationships	(1,608)	(1,766)	(1,807)	(1,719)
Total Interest Expense | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	(15)	(8)	(29)	(15)
Interest settlements reclassified from AOCI into net income on derivatives	(1,155)	(1,776)	(3,166)	(3,523)
Recognized on hedged items	(1,821)	(643)	(2,608)	(1,298)
Expense recognized on cash flow hedges	(2,991)	(2,427)	(5,803)	(4,836)
Total Interest Expense | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(23,443)	(12,141)	(41,599)	(23,949)
Premium/discount amortization recognized on hedged items	(484)	(257)	(924)	(478)
Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Gains on financial derivatives | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0	0	0
Gains/(losses) on fair value hedging relationships	0	0	0	0
Gains on financial derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0	0
Recognized on hedged items	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Gains on financial derivatives | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0	0	0
Premium/discount amortization recognized on hedged items	0	0	0	0
Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	3,418	(3,066)	19,492	1,227
Interest Rate Swap | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(16,512)	(18,532)	(32,386)	(37,059)
Income/(expense) related to interest settlements on fair value hedging relationships	10,537	11,337	22,797	23,044
Recognized on derivatives	200,746	(116,660)	339,277	167,733
Interest Rate Swap | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	3,911	(3,739)	4,614	(2,271)
Expense recognized on cash flow hedges	(1,955)	1,098	(2,883)	3,322
Interest Rate Swap | Interest Income Investments and Cash Equivalents | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(1,008)	(35)	(2,492)	(35)
Income/(expense) related to interest settlements on fair value hedging relationships	1,868	32	2,567	32
Recognized on derivatives	24,138	(176)	57,562	(176)
Interest Rate Swap | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Rate Swap | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(15,693)	(21,604)	(37,337)	(43,041)
Income/(expense) related to interest settlements on fair value hedging relationships	18,738	8,961	29,022	18,300
Recognized on derivatives	153,670	(48,680)	363,858	119,396
Interest Rate Swap | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Rate Swap | Interest Income Loans | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(4,459)	(6,704)	(11,405)	(13,275)
Income/(expense) related to interest settlements on fair value hedging relationships	9,210	4,931	14,883	9,847
Recognized on derivatives	109,419	(65,147)	241,351	80,624
Interest Rate Swap | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Rate Swap | Total Interest Expense | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	4,648	9,811	18,848	19,292
Income/(expense) related to interest settlements on fair value hedging relationships	(19,279)	(2,587)	(23,675)	(5,135)
Recognized on derivatives	(86,481)	(2,657)	(323,494)	(32,111)
Interest Rate Swap | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Expense recognized on cash flow hedges	0	0	0	0
Interest Rate Swap | Gains on financial derivatives | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	0	0	0	0
Income/(expense) related to interest settlements on fair value hedging relationships	0	0	0	0
Recognized on derivatives	0	0	0	0
Interest Rate Swap | Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	3,911	(3,739)	4,614	(2,271)
Expense recognized on cash flow hedges	(1,955)	1,098	(2,883)	3,322
Treasury futures | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	1,462	(425)	17,761	176
Treasury futures | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Treasury futures | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Treasury futures | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Treasury futures | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	0	0	0	0
Treasury futures | Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains/(losses) on financial derivatives	$ 1,462	$ (425)	$ 17,761	$ 176