v3.26.1
Other Comprehensive Income - Rollforward of AOCI (Details)
$ in Thousands
 6 Months Ended
Jun. 30, 2026
USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]  
Balance, beginning of period $ 5,147,551
Other comprehensive income (loss) before reclassifications (36,976)
Less: Amounts reclassified from AOCI (2,547)
Balance, end of period 5,013,359
Accumulated Other Comprehensive Income (Loss)  
AOCI Attributable to Parent, Net of Tax [Roll Forward]  
Balance, beginning of period (134,394)
Balance, end of period (168,823)
Net unrealized gains and (losses) on available-for-sale securities  
AOCI Attributable to Parent, Net of Tax [Roll Forward]  
Balance, beginning of period (120,686)
Other comprehensive income (loss) before reclassifications (36,976)
Less: Amounts reclassified from AOCI (2,247)
Balance, end of period (155,415)
Net benefit plan assets and (obligations) recognized in shareholders' equity  
AOCI Attributable to Parent, Net of Tax [Roll Forward]  
Balance, beginning of period (13,708)
Other comprehensive income (loss) before reclassifications 0
Less: Amounts reclassified from AOCI (300)
Balance, end of period $ (13,408)