Reclassifications Out of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses), net	$ (3,872)	$ 83	$ 748
Income tax (expense) benefit	(78,530)	(77,962)	(45,356)
Investment securities interest revenue	813,155	578,794	557,996
Long-term debt interest expense	(16,768)	(14,912)	(14,434)
Salaries and employee benefits expense	(276,205)	(241,443)	(224,060)
Other expense	(24,136)	(17,386)	(15,301)
Total before tax	356,002	347,763	209,445
Net income	277,472	269,801	164,089
Reclassifications Out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(10,434)	(1,100)	(899)
Reclassifications Out of AOCI | Realized gains (losses) on AFS securities:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Securities gains (losses), net	(3,872)	83	748
Income tax (expense) benefit	1,026	46	(191)
Net income	(2,846)	129	557
Reclassifications Out of AOCI | Amortization of unrealized losses on HTM securities transferred from AFS:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	2,167	0	173
Investment securities interest revenue	(9,049)	0	(723)
Net income	(6,882)	0	(550)
Reclassifications Out of AOCI | Losses on derivative instruments accounted for as cash flow hedges:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	69	156	91
Long-term debt interest expense	(269)	(608)	(359)
Net income	(200)	(452)	(268)
Reclassifications Out of AOCI | Amortization of defined benefit pension plan net periodic pension cost components:
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax (expense) benefit	174	267	219
Total before tax	(680)	(1,044)	(857)
Net income	(506)	(777)	(638)
Reclassifications Out of AOCI | Prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits expense	(313)	(469)	(531)
Reclassifications Out of AOCI | Actuarial losses
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other expense	$ (367)	$ (575)	$ (326)