v3.26.1
Accumulated Other Comprehensive (Loss), Net of Tax - Schedule of Component of Accumulated Other Comprehensive (Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance, beginning of period $ 9,573,649 $ 9,204,154 $ 9,492,236 $ 9,133,214
Other comprehensive income (loss) before reclassifications (16,979) 8,902 (96,481) 113,620
Amounts reclassified from accumulated other comprehensive (loss) income (191) 2,237 (394) 4,501
Other comprehensive (loss) income, net of tax (17,170) 11,139 (96,875) 118,121
Balance, end of period 9,760,749 9,337,617 9,760,749 9,337,617
Accumulated Other Comprehensive (Loss), Net of Tax        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance, beginning of period (430,549) (449,401) (350,844) (556,383)
Balance, end of period (447,719) (438,262) (447,719) (438,262)
Investment Securities Available- for-Sale        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance, beginning of period (408,728) (423,737) (334,113) (520,318)
Other comprehensive income (loss) before reclassifications (11,246) 8,858 (85,861) 105,824
Amounts reclassified from accumulated other comprehensive (loss) income 0 0 0 (385)
Other comprehensive (loss) income, net of tax (11,246) 8,858 (85,861) 105,439
Balance, end of period (419,974) (414,879) (419,974) (414,879)
Derivative Financial Instruments        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance, beginning of period (1,391) 524 3,741 (9,600)
Other comprehensive income (loss) before reclassifications (5,733) 44 (10,620) 7,796
Amounts reclassified from accumulated other comprehensive (loss) income (232) 1,960 (477) 4,332
Other comprehensive (loss) income, net of tax (5,965) 2,004 (11,097) 12,128
Balance, end of period (7,356) 2,528 (7,356) 2,528
Defined Benefit Pension and Other Postretirement Benefit Plans        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Balance, beginning of period (20,430) (26,188) (20,472) (26,465)
Other comprehensive income (loss) before reclassifications 0 0 0 0
Amounts reclassified from accumulated other comprehensive (loss) income 41 277 83 554
Other comprehensive (loss) income, net of tax 41 277 83 554
Balance, end of period $ (20,389) $ (25,911) $ (20,389) $ (25,911)