v3.25.3
Capital (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Jun. 30, 2025
Dec. 31, 2024
Jun. 30, 2024
Dec. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]                
AOCI balance $ 4,686,851 $ 5,961,499 $ 4,686,851 $ 5,961,499 $ 5,061,239 $ 5,634,068 $ 5,611,431 $ 5,679,738
Net unrealized gains (losses) on AFS securities 38,164 30,517 17,745 69,307        
Net Unrealized Gains(Losses)                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
AOCI balance (11,845) (3,555) (11,845) (3,555) (50,009) (29,173) (34,072) (72,862)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax 0 0 417 0        
Pension and Post Retirement Plans                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
AOCI balance (4,729) (1,489) (4,729) (1,489) (4,877) (1,347) (1,519) 374
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent 148 30 (3,382) (1,863)        
AOCI Attributable to Parent [Member]                
Accumulated Other Comprehensive Income (Loss) [Line Items]                
AOCI balance (16,574) (5,044) (16,574) (5,044) $ (54,886) $ (30,520) $ (35,591) $ (72,488)
Net unrealized gains (losses) 38,164 30,517 17,745 69,307        
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent $ 148 $ 30 (3,382) $ (1,863)        
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax     $ 417