Accumulated Other Comprehensive (Loss), Net of Tax - Schedule of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	$ 9,204,154	$ 8,747,498	$ 9,133,214	$ 8,689,996
Other comprehensive income (loss) before reclassifications	8,902	(55,071)	113,620	(135,348)
Amounts reclassified from accumulated other comprehensive (loss) income	2,237	43,273	4,501	58,020
Total	11,139	(11,798)	118,121	(77,328)
Balance, end of period	9,337,617	8,809,268	9,337,617	8,809,268
Accumulated Other Comprehensive (Loss), Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(449,401)	(616,101)	(556,383)	(550,571)
Total	11,139	(11,798)	118,121	(77,328)
Balance, end of period	(438,262)	(627,899)	(438,262)	(627,899)
Investment Securities Available- for-Sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(423,737)	(553,721)	(520,318)	(517,450)
Other comprehensive income (loss) before reclassifications	8,858	(43,970)	105,824	(86,560)
Amounts reclassified from accumulated other comprehensive (loss) income	0	34,161	(385)	40,480
Total	8,858	(9,809)	105,439	(46,080)
Balance, end of period	(414,879)	(563,530)	(414,879)	(563,530)
Derivative Financial Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	524	(32,858)	(9,600)	(2,869)
Other comprehensive income (loss) before reclassifications	44	(10,243)	7,796	(48,181)
Amounts reclassified from accumulated other comprehensive (loss) income	1,960	8,633	4,332	16,582
Total	2,004	(1,610)	12,128	(31,599)
Balance, end of period	2,528	(34,468)	2,528	(34,468)
Defined Benefit Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance, beginning of period	(26,188)	(29,522)	(26,465)	(30,252)
Other comprehensive income (loss) before reclassifications	0	(858)	0	(607)
Amounts reclassified from accumulated other comprehensive (loss) income	277	479	554	958
Total	277	(379)	554	351
Balance, end of period	$ (25,911)	$ (29,901)	$ (25,911)	$ (29,901)