v3.26.1
Shareholders' Equity - Net Change in Components of Accumulated Other Comprehensive Income (Loss) and the Related Tax Effects (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Other comprehensive income (loss), before tax amount $ (18,414) $ 46,608
Other Comprehensive Income (Loss), Tax, Total 4,603 (11,651)
Other comprehensive income (loss), before reclassifications, net of tax amount (14,576) 32,928
Reclassification from accumulated other comprehensive income, current period, net of tax amount 765 2,029
Other comprehensive income (loss), net of tax amount (13,811) 34,957
Securities Available for Sale and Transferred Securities [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Other comprehensive income (loss), before reclassifications, before tax amount (16,686) 32,599
Reclassification from accumulated other comprehensive income, current period, before tax amount 0 0
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, before tax amount 2,959 3,425
Other comprehensive income (loss), before tax amount (13,727) 36,024
Other comprehensive income (loss), before reclassifications, tax (expense) benefit 4,171 (8,149)
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit 0 0
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, tax (expense) benefit (740) (856)
Other Comprehensive Income (Loss), Tax, Total 3,431 (9,005)
Other comprehensive income (loss), before reclassifications, net of tax amount (12,515) 24,450
Reclassification from accumulated other comprehensive income, current period, net of tax amount 0 0
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, net of tax amount 2,219 2,569
Other comprehensive income (loss), net of tax amount (10,296) 27,019
Net Change in Prior Service Costs [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Reclassification from accumulated other comprehensive income, current period, before tax amount 0 4
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit 0 (1)
Reclassification from accumulated other comprehensive income, current period, net of tax amount 0 3
Recognized Net Loss Due to Lump Sum Settlements [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Reclassification from accumulated other comprehensive income, current period, before tax amount 0 (50)
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit 0 12
Reclassification from accumulated other comprehensive income, current period, net of tax amount 0 (38)
Change in Net Actuarial Loss [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Reclassification from accumulated other comprehensive income, current period, before tax amount 85 71
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit (21) (17)
Reclassification from accumulated other comprehensive income, current period, net of tax amount 64 54
Pension and Other Postretirement Benefit Plans [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Reclassification from accumulated other comprehensive income, current period, before tax amount 85 25
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit (21) (6)
Reclassification from accumulated other comprehensive income, current period, net of tax amount 64 19
Cash Flow Hedge Derivatives [Member]    
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Other comprehensive income (loss), before reclassifications, before tax amount (5,707) 7,879
Reclassification from accumulated other comprehensive income, current period, before tax amount 935 2,680
Other comprehensive income (loss), before tax amount (4,772) 10,559
Other comprehensive income (loss), before reclassifications, tax (expense) benefit 1,427 (1,970)
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit (234) (670)
Other Comprehensive Income (Loss), Tax, Total 1,193 (2,640)
Other comprehensive income (loss), before reclassifications, net of tax amount (4,280) 5,909
Reclassification from accumulated other comprehensive income, current period, net of tax amount 701 2,010
Other comprehensive income (loss), net of tax amount $ (3,579) $ 7,919