v3.26.1
ACCUMULATED OTHER COMPREHENSIVE LOSS - Change in Accumulated Other Comprehensive Loss by Component (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Unrealized net holding losses on available-for-sale debt securities:[Y    
Beginning balance $ (354,940) $ (567,338)
Other comprehensive (loss) income (6,168) 84,061
Ending balance (361,108) (483,277)
Adjustment of pension and postretirement benefit plans:    
Beginning balance 390 782
Other comprehensive (loss) income 0 0
Ending balance $ 390 $ 782