v3.26.1
Available for Sale Securities (Details)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Jun. 30, 2026
USD ($)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost $ 13,839,238   $ 13,839,238   $ 13,739,191
Available-for-sale Securities, Fair Value 13,582,780   13,582,780   13,606,625
Available-for-sale Securities, Gross Unrealized Gain 58,953   58,953   141,234
Available-for-sale Securities, Gross Unrealized Loss (315,411)   (315,411)   (273,800)
Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract]          
Proceeds from sales of available-for-sale securities 268,479 $ 0 268,479 $ 0  
Available-for-sale Securities, Gross realized gains 250 0 250 0  
Debt Securities, Available-for-Sale, Realized Loss 4,895 0 4,895 0  
Available-for-sale Securities, Related federal and state income tax expense (benefit) (1,098) $ 0 (1,098) $ 0  
Asset Pledged as Collateral with Right          
Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract]          
Pledged Securities 11,700,000   11,700,000   11,500,000
Fixed Maturity Securities [Member]          
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]          
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis 297,391   297,391    
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis 1,922,586   1,922,586    
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis 249,043   249,043    
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis 414,039   414,039    
Available-for-sale Securities, Debt Maturities, Allocated and Single Maturity Date, Amortized Cost 2,883,059   2,883,059    
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]          
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value 294,662   294,662    
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value 1,822,969   1,822,969    
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value 242,010   242,010    
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value 407,685   407,685    
Available-for-sale Securities, Debt Maturities, Allocated and Single Maturity Date, Fair Value $ 2,767,326   $ 2,767,326    
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity [1] 4.76   4.76    
U.S. Treasury [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost $ 1,000   $ 1,000   1,001
Available-for-sale Securities, Fair Value 989   989   980
Available-for-sale Securities, Gross Unrealized Gain 0   0   0
Available-for-sale Securities, Gross Unrealized Loss (11)   (11)   (21)
Municipal securities [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost 116,831   116,831   190,917
Available-for-sale Securities, Fair Value 112,845   112,845   184,273
Available-for-sale Securities, Gross Unrealized Gain 0   0   0
Available-for-sale Securities, Gross Unrealized Loss (3,986)   (3,986)   (6,644)
Commercial agency mortgage-backed securities [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost 2,764,728   2,764,728   3,240,728
Available-for-sale Securities, Fair Value 2,653,019   2,653,019   3,126,244
Available-for-sale Securities, Gross Unrealized Gain 3,235   3,235   7,622
Available-for-sale Securities, Gross Unrealized Loss (114,944)   (114,944)   (122,106)
Other debt securities [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost 500   500   500
Available-for-sale Securities, Fair Value 473   473   473
Available-for-sale Securities, Gross Unrealized Gain 0   0   0
Available-for-sale Securities, Gross Unrealized Loss (27)   (27)   (27)
Residential Mortgage Backed Securities [Member]          
Debt Securities, Available-for-sale, Maturity, Amortized Cost, Rolling Maturity [Abstract]          
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost [2] 10,956,179   10,956,179    
Debt Securities, Available-for-sale, Maturity, Fair Value, Rolling Maturity [Abstract]          
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value $ 10,815,454   10,815,454    
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities 4 years 3 months 18 days        
Residential agency mortgage-backed securities [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost $ 10,247,618   10,247,618   9,593,919
Available-for-sale Securities, Fair Value 10,129,404   10,129,404   9,598,627
Available-for-sale Securities, Gross Unrealized Gain 46,193   46,193   121,838
Available-for-sale Securities, Gross Unrealized Loss (164,407)   (164,407)   (117,130)
Residential non-agency mortgage-backed securities [Member]          
Debt Securities, Available-for-sale [Line Items]          
Available-for-sale Securities, Amortized Cost 708,561   708,561   712,126
Available-for-sale Securities, Fair Value 686,050   686,050   696,028
Available-for-sale Securities, Gross Unrealized Gain 9,525   9,525   11,774
Available-for-sale Securities, Gross Unrealized Loss $ (32,036)   $ (32,036)   $ (27,872)
[1] Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalty.
[2] The average expected lives of residential mortgage-backed securities were 4.3 years based upon current prepayment assumptions.