v3.25.1
Derivative and Other Hedging Instruments (Fair Value Information) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Dec. 31, 2023
Derivative [Line Items]        
Derivative asset, fair value $ 98,000   $ 205,000  
Derivative liability, fair value (70,000)   (94,000)  
Derivative assets, at fair value 98,000   205,000  
Derivative Liability (70,000)   (94,000)  
U.S. Treasury securities 3,280,000   1,575,000  
U.S. Treasury Securities - short (17,180,000)   (16,676,000)  
Total - (short)/long, net (13,900,000)   (15,101,000)  
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (1,011,000) $ 1,102,000    
Net Fair Value of Interest Rate Swaps Excluding the Recognition of Variation Margin Settlements as a Reduction of Carrying Value 1,400,000   2,300,000  
TBA and Forward Settling Agency Securities [Member]        
Derivative [Line Items]        
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period 27,967,000 25,390,000    
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period   (22,071,000)    
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net 77,000 (58,000)    
Derivative, Fair Value, Net 44,000   (26,000)  
Interest Rate Swap [Member]        
Derivative [Line Items]        
Derivative Liability, Notional Amount 47,796,000   39,646,000  
Derivative liability, fair value (3,000)   0  
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period 8,150,000 5,170,000    
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period 0 (5,250,000)    
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (569,000) 658,000    
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]        
Derivative [Line Items]        
Derivative asset, fair value 2,000   22,000  
Interest Rate Swaption [Member]        
Derivative [Line Items]        
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period 1,500,000 0    
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period (1,500,000) (1,250,000)    
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (19,000) 33,000    
Interest Rate Swaption [Member] | Fair Value, Inputs, Level 2 [Member]        
Derivative [Line Items]        
Derivative asset, fair value 17,000   39,000  
Purchases Of TBAs And Forward Settling Agency Securities [Member]        
Derivative [Line Items]        
Derivative liability, fair value (28,000)   (87,000)  
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period (27,111,000)      
US Treasury Securities [Member]        
Derivative [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (100,000) 186,000    
Derivative, Fair Value, Net (38,000)   83,000  
SOFR Futures Contracts        
Derivative [Line Items]        
Derivative liability, fair value 0   (7,000)  
Derivative assets, at fair value 6,000   0  
US Treasury Securities [Member] | Fair Value, Recurring [Member] | Future [Member] | Fair Value, Inputs, Level 1 [Member]        
Derivative [Line Items]        
Derivative assets, at fair value (1,000)   (83,000)  
Derivative Liability (39,000)   0  
TBA and Forward Settling Agency Securities [Member] | Fair Value, Recurring [Member] | Purchases Of TBAs And Forward Settling Agency Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Derivative [Line Items]        
Derivative assets, at fair value 72,000   61,000  
Sale Of TBA And Forward Settling Agency Securities [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]        
Derivative [Line Items]        
Derivative Liability (28,000)   (87,000)  
Sale Of TBA And Forward Settling Agency Securities [Member] | Fair Value, Recurring [Member] | Purchases Of TBAs And Forward Settling Agency Securities [Member] | Fair Value, Inputs, Level 2 [Member]        
Derivative [Line Items]        
Derivative assets, at fair value 72,000      
Short [Member] | US Treasury Securities [Member]        
Derivative [Line Items]        
Notional Amount Of Derivatives Not Designated As Hedging Instruments Additions During The Period 3,821,000 3,101,000    
Notional Amount Of Derivatives Not Designated As Hedging Instruments Settlement Expiration During The Period (3,977,000) (1,641,000)    
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (460,000) 338,000    
Long [Member] | US Treasury Securities [Member]        
Derivative [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net 60,000 (43,000)    
Debt Securities, Trading, and Equity Securities, FV-NI 3,216,000 1,815,000 $ 1,585,000 $ 1,492,000
Trading Securities Added During the Period 5,388,000 1,669,000    
Notional Amount Of Trading Securities Settlement Expiration During The Period (3,757,000) (1,346,000)    
Long [Member] | SOFR Futures Contracts        
Derivative [Line Items]        
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net $ 10,000 $ (10,000)