v3.26.3
Investment Securities - Schedule of Available-for-sale Investment Securities Portfolios (Details) - USD ($)
Sep. 30, 2026
Dec. 31, 2025
Sep. 30, 2025
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value $ 5,290,440,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (355,869,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 2,250,301,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (581,810,000)    
Total, fair value 7,540,741,000    
Total, unrealized losses (937,679,000)    
Available-for-sale securities, at fair value 7,569,498,000 $ 6,236,263,000 $ 5,274,124,000
U.S. government agencies      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 0    
Continuous unrealized losses existing for less than 12 months, unrealized losses 0    
Continuous unrealized losses existing for greater than 12 months, fair value 43,831,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (6,169,000)    
Total, fair value 43,831,000    
Total, unrealized losses (6,169,000)    
Available-for-sale securities, at fair value 43,831,000 47,471,000 46,511,000
Municipal      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 127,329,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (4,295,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 27,222,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (2,626,000)    
Total, fair value 154,551,000    
Total, unrealized losses (6,921,000)    
Available-for-sale securities, at fair value 164,324,000 162,166,000 194,244,000
Financial issuers      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 0    
Continuous unrealized losses existing for less than 12 months, unrealized losses 0    
Continuous unrealized losses existing for greater than 12 months, fair value 73,056,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (1,944,000)    
Total, fair value 73,056,000    
Total, unrealized losses (1,944,000)    
Available-for-sale securities, at fair value 73,056,000 76,296,000 79,372,000
Other      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 962,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (38,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 0    
Continuous unrealized losses existing for greater than 12 months, unrealized losses 0    
Total, fair value 962,000    
Total, unrealized losses (38,000)    
Available-for-sale securities, at fair value 962,000 999,000 1,000,000
Residential mortgage-backed securities      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 4,185,360,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (311,685,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 1,885,320,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (539,205,000)    
Total, fair value 6,070,680,000    
Total, unrealized losses (850,890,000)    
Available-for-sale securities, at fair value 6,077,176,000 5,156,683,000 4,359,462,000
Commercial (multi-family) mortgage-backed securities      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 199,929,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (14,351,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 160,228,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (13,891,000)    
Total, fair value 360,157,000    
Total, unrealized losses (28,242,000)    
Available-for-sale securities, at fair value 360,157,000 276,553,000 228,338,000
Collateralized mortgage obligations      
Available-for-sale securities      
Continuous unrealized losses existing for less than 12 months, fair value 776,860,000    
Continuous unrealized losses existing for less than 12 months, unrealized losses (25,500,000)    
Continuous unrealized losses existing for greater than 12 months, fair value 60,644,000    
Continuous unrealized losses existing for greater than 12 months, unrealized losses (17,975,000)    
Total, fair value 837,504,000    
Total, unrealized losses (43,475,000)    
Available-for-sale securities, at fair value 846,992,000 509,060,000 357,161,000
Mortgage-backed securities, subprime      
Available-for-sale securities      
Available-for-sale securities, at fair value $ 0 $ 0 $ 0