Financial Derivatives - Schedule of Net Income/(Expense) Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Investments and cash equivalents	$ 18,660	$ 42,144	$ 81,522
Interest Income Farmer Mac Guaranteed Securities and USDA Securities	163,547	227,691	333,896
Interest Income Loans	242,582	233,699	229,675
Total interest expense	(204,014)	(312,946)	(471,958)
(Losses)/gains on financial derivatives	(3,348)	(246)	5,282
Total	217,427	148,198	96,895
Expense recognized on cash flow hedges	19,394	16,053	20,945
Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(179,407)	230,330	208,311
Gains/(losses) on fair value hedging relationships	(1,515)	(9,184)	(7,907)
Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	(37)	(13)	(4)
Interest settlements reclassified from AOCI into net income on derivatives	(7,399)	(5,570)	1,166
Recognized on hedged items	(2,657)	(4,553)	(10,569)
Expense recognized on cash flow hedges	(10,093)	(10,136)	(9,407)
Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	117,046	115,733	99,652
Discount amortization recognized on hedged items	(1,118)	(745)	(631)
No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	(3,348)	(246)	5,282
Interest Income Investments and Cash Equivalents | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(1,218)
Gains/(losses) on fair value hedging relationships	470
Interest Income Investments and Cash Equivalents | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	0
Interest settlements reclassified from AOCI into net income on derivatives	0
Recognized on hedged items	0
Expense recognized on cash flow hedges	0
Interest Income Investments and Cash Equivalents | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	1,792
Discount amortization recognized on hedged items	0
Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(176,304)	202,624	181,144
Gains/(losses) on fair value hedging relationships	773	(3,657)	(3,334)
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0
Recognized on hedged items	0	0	0
Expense recognized on cash flow hedges	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	119,896	126,170	118,609
Discount amortization recognized on hedged items	0	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Interest Income Loans | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(97,502)	73,426	43,194
Gains/(losses) on fair value hedging relationships	(43)	(3,139)	(6,947)
Interest Income Loans | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0
Recognized on hedged items	0	0	0
Expense recognized on cash flow hedges	0	0	0
Interest Income Loans | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	46,842	40,793	26,352
Discount amortization recognized on hedged items	0	0	0
Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Total Interest Expense | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	95,617	(45,720)	(16,027)
Gains/(losses) on fair value hedging relationships	(2,715)	(2,388)	2,374
Total Interest Expense | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	(37)	(13)	(4)
Interest settlements reclassified from AOCI into net income on derivatives	(7,399)	(5,570)	1,166
Recognized on hedged items	(2,657)	(4,553)	(10,569)
Expense recognized on cash flow hedges	(10,093)	(10,136)	(9,407)
Total Interest Expense | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(51,484)	(51,230)	(45,309)
Discount amortization recognized on hedged items	(1,118)	(745)	(631)
Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Losses on financial derivatives | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0	0
Gains/(losses) on fair value hedging relationships	0	0	0
Losses on financial derivatives | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Discount amortization recognized on hedged items	0	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0	0
Recognized on hedged items	0	0	0
Expense recognized on cash flow hedges	0	0	0
Losses on financial derivatives | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0	0
Discount amortization recognized on hedged items	0	0	0
Losses on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	(3,348)	(246)	5,282
Interest Rate Swap | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(70,880)	(52,805)	(10,457)
Income/(expense) related to interest settlements on fair value hedging relationships	45,048	62,183	88,564
Recognized on derivatives	177,892	(239,514)	(216,218)
Interest Rate Swap | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	(5,816)	(4,204)	10,321
Expense recognized on cash flow hedges	3,259	5,808	(4,213)
Interest Rate Swap | Interest Income Investments and Cash Equivalents | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(1,002)
Income/(expense) related to interest settlements on fair value hedging relationships	790
Recognized on derivatives	1,688
Interest Rate Swap | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0
Expense recognized on cash flow hedges	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	(85,302)	(60,056)	(2,177)
Income/(expense) related to interest settlements on fair value hedging relationships	34,594	66,114	116,432
Recognized on derivatives	177,077	(206,281)	(184,478)
Interest Rate Swap | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Expense recognized on cash flow hedges	0	0	0
Interest Rate Swap | Interest Income Loans | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(27,167)	(19,135)	(2,053)
Income/(expense) related to interest settlements on fair value hedging relationships	19,675	21,658	24,299
Recognized on derivatives	97,459	(76,565)	(50,141)
Interest Rate Swap | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Expense recognized on cash flow hedges	0	0	0
Interest Rate Swap | Total Interest Expense | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	42,591	26,386	(6,227)
Income/(expense) related to interest settlements on fair value hedging relationships	(10,011)	(25,589)	(52,167)
Recognized on derivatives	(98,332)	43,332	18,401
Interest Rate Swap | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Expense recognized on cash flow hedges	0	0	0
Interest Rate Swap | Losses on financial derivatives | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	0	0	0
Income/(expense) related to interest settlements on fair value hedging relationships	0	0	0
Recognized on derivatives	0	0	0
Interest Rate Swap | Losses on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	(5,816)	(4,204)	10,321
Expense recognized on cash flow hedges	3,259	5,808	(4,213)
Treasury futures | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	(791)	(1,850)	(826)
Treasury futures | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0
Treasury futures | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Treasury futures | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Treasury futures | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	0	0	0
Treasury futures | Losses on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
(Losses)/gains on financial derivatives	$ (791)	$ (1,850)	$ (826)