v3.26.1
Other Comprehensive Income (Loss) - Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance $ 3,866,918 $ 2,727,105 $ 3,884,905 $ 2,678,318
Ending balance 3,871,378 3,778,854 3,871,378 3,778,854
Accumulated Other Comprehensive Income (Loss)        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (99,624) (121,621) (89,732) (142,608)
Other comprehensive income (loss) before reclassification (6,317) 9,205 (20,394) 36,329
Amounts reclassified from accumulated other comprehensive income 842 940 1,683 1,869
Tax expense (benefit) 1,431 (2,565) 4,775 (9,631)
Other comprehensive (loss) income, net of tax (4,044) 7,580 (13,936) 28,567
Ending balance (103,668) (114,041) (103,668) (114,041)
Unrealized Holding Gains (Losses) on Available-for-Sale Securities        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (68,409) (83,919) (56,542) (103,889)
Other comprehensive income (loss) before reclassification (9,195) 9,040 (25,086) 35,727
Amounts reclassified from accumulated other comprehensive income 0 0 0 0
Tax expense (benefit) 2,383 (2,282) 6,407 (8,999)
Other comprehensive (loss) income, net of tax (6,812) 6,758 (18,679) 26,728
Ending balance (75,221) (77,161) (75,221) (77,161)
Amortization of unrealized holding losses on securities transferred to held to maturity        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (38,482) (46,780) (40,435) (49,045)
Other comprehensive income (loss) before reclassification 2,605 2,840 5,230 5,884
Amounts reclassified from accumulated other comprehensive income 0 0 0 0
Tax expense (benefit) (667) (727) (1,339) (1,506)
Other comprehensive (loss) income, net of tax 1,938 2,113 3,891 4,378
Ending balance (36,544) (44,667) (36,544) (44,667)
Unrealized Gains (Losses) on Derivative Instruments        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance 13,565 16,107 13,598 17,429
Other comprehensive income (loss) before reclassification 199 (2,775) (686) (5,481)
Amounts reclassified from accumulated other comprehensive income 842 940 1,683 1,869
Tax expense (benefit) (266) 470 (255) 925
Other comprehensive (loss) income, net of tax 775 (1,365) 742 (2,687)
Ending balance 14,340 14,742 14,340 14,742
Defined Benefit Pension and Post-retirement Benefit Plans        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (6,298) (7,029) (6,353) (7,103)
Other comprehensive income (loss) before reclassification 74 100 148 199
Amounts reclassified from accumulated other comprehensive income 0 0 0 0
Tax expense (benefit) (19) (26) (38) (51)
Other comprehensive (loss) income, net of tax 55 74 110 148
Ending balance $ (6,243) $ (6,955) $ (6,243) $ (6,955)