v3.26.1
ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Loss        
Beginning balance $ 2,672,565 $ 2,332,214 $ 2,466,667 $ 2,304,983
Other comprehensive loss before reclassifications     (3,458) (1,296)
Amounts reclassified from accumulated other comprehensive loss     0 6
Period change 15,268 336 (3,458) (1,290)
Ending balance 2,697,177 2,347,952 2,697,177 2,347,952
Total        
Accumulated Other Comprehensive Loss        
Beginning balance (148,861) (190,311) (130,135) (188,685)
Period change 15,268 336 (3,458) (1,290)
Ending balance (133,593) (189,975) (133,593) (189,975)
Unrealized Gains (Losses) on Securities Available for Sale        
Accumulated Other Comprehensive Loss        
Beginning balance     (131,902) (188,412)
Other comprehensive loss before reclassifications     (3,458) (1,296)
Amounts reclassified from accumulated other comprehensive loss     0 6
Period change     (3,458) (1,290)
Ending balance (135,360) (189,702) (135,360) (189,702)
Unrealized Gains (Losses) on Defined Benefit Plans        
Accumulated Other Comprehensive Loss        
Beginning balance     1,767 (273)
Other comprehensive loss before reclassifications     0 0
Amounts reclassified from accumulated other comprehensive loss     0 0
Period change     0 0
Ending balance $ 1,767 $ (273) $ 1,767 $ (273)