v3.26.1
Accumulated Other Comprehensive Income (Loss) - Accumulated Other Comprehensive Income (Loss) Balances, Net of Tax (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Net Unrealized Holding Gain (Loss) on Securities Available for Sale, Net of Tax [Member]    
Accumulated Other Comprehensive Income (Loss) [Abstract]    
Balance $ (12,055) $ (21,713)
Other comprehensive income (loss) - before reclassifications (1,266) 3,948
Amount reclassified from accumulated other comprehensive income (loss) 0 0
Other comprehensive income (loss), net of tax (1,266) 3,948
Balance (13,321) (17,765)
Net Change in Overfunded Position in Pension and Postretirement Plans Arising During the Year, Net of Tax [Member]    
Accumulated Other Comprehensive Income (Loss) [Abstract]    
Balance 26,962 21,266
Other comprehensive income (loss) - before reclassifications 0 0
Amount reclassified from accumulated other comprehensive income (loss) 0 0
Other comprehensive income (loss), net of tax 0 0
Balance 26,962 21,266
Net Change in Net Actuarial Gain and Prior Service Cost on Pension and Postretirement Benefit Plans, Net of Tax [Member]    
Accumulated Other Comprehensive Income (Loss) [Abstract]    
Balance (4,883) (3,414)
Other comprehensive income (loss) - before reclassifications 0 0
Amount reclassified from accumulated other comprehensive income (loss) (517) (219)
Other comprehensive income (loss), net of tax (517) (219)
Balance (5,400) (3,633)
Accumulated Other Comprehensive Income (Loss) [Member]    
Accumulated Other Comprehensive Income (Loss) [Abstract]    
Balance 10,024 (3,861)
Other comprehensive income (loss) - before reclassifications (1,266) 3,948
Amount reclassified from accumulated other comprehensive income (loss) (517) (219)
Other comprehensive income (loss), net of tax (1,783) 3,729
Balance $ 8,241 $ (132)