Accumulated Other Comprehensive (Loss), Net of Tax - Schedule of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 9,133,214	$ 8,689,996
Other comprehensive income before reclassifications	104,718	(80,277)
Amounts reclassified from accumulated other comprehensive (loss)	2,264	14,747
Total	106,982	(65,530)
Balance, end of period	9,204,154	8,747,498
Accumulated Other Comprehensive (Loss), Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(556,383)	(550,571)
Balance, end of period	(449,401)	(616,101)
Investment Securities Available- for-Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(520,318)	(517,450)
Other comprehensive income before reclassifications	96,966	(42,591)
Amounts reclassified from accumulated other comprehensive (loss)	(385)	6,320
Total	96,581	(36,271)
Balance, end of period	(423,737)	(553,721)
Derivative Financial Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(9,600)	(2,869)
Other comprehensive income before reclassifications	7,752	(37,937)
Amounts reclassified from accumulated other comprehensive (loss)	2,372	7,948
Total	10,124	(29,989)
Balance, end of period	524	(32,858)
Defined Benefit Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(26,465)	(30,252)
Other comprehensive income before reclassifications	0	251
Amounts reclassified from accumulated other comprehensive (loss)	277	479
Total	277	730
Balance, end of period	$ (26,188)	$ (29,522)