v3.26.1
Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, Beginning of Period $ 1,861,760 $ 1,668,499
Other Comprehensive Income Before Reclassifications, net of tax (210) 211
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 9 (9)
Total Other Comprehensive Income (Loss) (201) 202
Balance, End of Period 1,907,792 1,717,361
Accumulated Other Comprehensive Income (Loss)    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, Beginning of Period 470 532
Total Other Comprehensive Income (Loss) (201) 202
Balance, End of Period 269 734
Pension and Other Postretirement Benefits    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, Beginning of Period 70 373
Other Comprehensive Income Before Reclassifications, net of tax 0 0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 0 (11)
Total Other Comprehensive Income (Loss) 0 (11)
Balance, End of Period 70 362
Net Unrealized Gains (Losses) on Available-for-Sale Securities    
AOCI Attributable to Parent, Net of Tax [Roll Forward]    
Balance, Beginning of Period 400 159
Other Comprehensive Income Before Reclassifications, net of tax (210) 211
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) 9 2
Total Other Comprehensive Income (Loss) (201) 213
Balance, End of Period $ 199 $ 372