v3.26.1
Investment Securities - Additional Information (Details)
 3 Months Ended 9 Months Ended
Mar. 31, 2026
USD ($)
security
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Schedule of Available-for-sale Securities [Line Items]        
Carrying value of investment securities $ 2,670,000,000   $ 2,650,000,000  
Investment securities pledged as collateral 157,400,000   155,800,000  
Available for sale securities sold 0 $ 0    
Recovery of credit losses 0 0 (2,195,000)  
Allowance for credit losses, HTM 2,005,000 2,005,000 2,005,000 $ 2,005,000
Allowance for credit losses, AFS 0 $ 2,195,000 0 $ 2,195,000
Debt securities available for sale unrealized loss position (239,492,000)   (223,382,000)  
Fair value of unrealized losses $ 236,414,000   222,629,000  
Percentage of Company's investment portfolio 43.80%      
Maturity description of investment portfolio five years or less      
Number of investment securities available for sale | security 1,452      
Number of investment in debt securities available-for-sale unrealized loss position | security 1,196      
Number of investment securities held to maturity | security 511      
Number of investments in debt securities held-to-maturity unrealized loss position | security 498      
Unrealized losses $ (111,826,000)   (98,681,000)  
U.S. government-sponsored enterprises        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, HTM 0   0  
Allowance for credit losses, AFS 0   0  
Debt securities available for sale unrealized loss position (7,389,000)   (7,107,000)  
Fair value of unrealized losses $ 7,373,000   7,075,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 53      
Number of investments in debt securities held-to-maturity unrealized loss position | security 5      
Unrealized losses $ (1,758,000)   (1,391,000)  
U.S. government-sponsored mortgage-backed securities        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, HTM 0   0  
Allowance for credit losses, AFS 0   0  
Debt securities available for sale unrealized loss position (143,819,000)   (133,999,000)  
Fair value of unrealized losses $ 143,260,000   133,863,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 609      
Number of investments in debt securities held-to-maturity unrealized loss position | security 16      
Unrealized losses $ (4,144,000)   (3,258,000)  
Private mortgage-backed securities        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, AFS 0   0  
Debt securities available for sale unrealized loss position (8,110,000)   (6,984,000)  
Fair value of unrealized losses $ 8,092,000   6,984,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 29      
Non-government-sponsored asset backed securities        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, AFS $ 0   0  
Debt securities available for sale unrealized loss position (1,137,000)   (927,000)  
Fair value of unrealized losses $ 1,092,000   914,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 13      
State and political subdivisions        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, HTM $ 2,005,000   2,005,000  
Allowance for credit losses, AFS 0   0  
Debt securities available for sale unrealized loss position (70,739,000)   (65,403,000)  
Fair value of unrealized losses $ 68,734,000   64,898,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 441      
Number of investments in debt securities held-to-maturity unrealized loss position | security 477      
Unrealized losses $ (105,924,000)   (94,032,000)  
Other securities        
Schedule of Available-for-sale Securities [Line Items]        
Allowance for credit losses, AFS 0   0  
Debt securities available for sale unrealized loss position (8,298,000)   (8,962,000)  
Fair value of unrealized losses $ 7,863,000   $ 8,895,000  
Number of investment in debt securities available-for-sale unrealized loss position | security 51