v3.25.2
Investment Securities - Credit Quality Indicators (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity $ 2,570.7 $ 2,688.4
U.S. Treasury notes    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 100.0 99.8
State, county, and municipal securities    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 175.8 176.3
Obligations of U.S. government agencies    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 466.8 470.1
Corporate securities    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 40.0 57.0
Commercial Mortgage-Backed Securities    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 369.7 374.9
Residential Mortgage Backed Securities    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity 1,013.4 1,082.5
Collateralized Mortgage Obligations    
Schedule of Held-to-maturity Securities [Line Items]    
Investment securities classified as held to maturity $ 405.0 $ 427.8