Accumulated Other Comprehensive Loss - Changes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Pre-tax Amount
Other comprehensive income , Pre-tax Amount	$ 90,656	$ (49,090)	$ 105,764	$ (12,924)
Income Tax Benefit (Expense)
Other comprehensive loss, Income Tax Benefit (Expense)	(24,182)	13,095	(28,212)	3,447
Net of tax
Balance	2,550,312	2,359,738	2,486,066	2,269,005
Other comprehensive income (loss)	66,474	(35,995)	77,552	(9,477)
Balance	2,648,034	2,351,009	2,648,034	2,351,009
Accumulated Other Comprehensive Income (Loss)
Pre-tax Amount
Accumulated other comprehensive loss, beginning balance, Pre-tax Amount	(707,992)	(835,647)	(723,100)	(871,813)
Accumulated other comprehensive loss, ending balance, Pre-tax Amount	(617,336)	(884,737)	(617,336)	(884,737)
Income Tax Benefit (Expense)
Accumulated other comprehensive loss, beginning balance, Income Tax Benefit (Expense)	188,860	222,911	192,890	232,559
Accumulated other comprehensive loss, ending balance, Income Tax Benefit (Expense)	164,678	236,006	164,678	236,006
Net of tax
Balance	(519,132)	(612,736)	(530,210)	(639,254)
Other comprehensive income (loss)	66,474	(35,995)	77,552	(9,477)
Balance	(452,658)	(648,731)	(452,658)	(648,731)
Investment securities
Pre-tax Amount
Unrealized net gains (losses) arising during the period, Pre-tax Amount	76,226	(61,874)	68,517	(50,861)
Other comprehensive income , Pre-tax Amount	90,148	(50,440)	104,264	(14,655)
Income Tax Benefit (Expense)
Unrealized net gains (losses) arising during the period, Income Tax Benefit (Expense)	(20,333)	16,505	(18,277)	13,567
Other comprehensive loss, Income Tax Benefit (Expense)	(24,047)	13,455	(27,812)	3,909
Net of tax
Unrealized net gains (losses) arising during the period, Net of tax	55,893	(45,369)	50,240	(37,294)
Other comprehensive income (loss)	66,101	(36,985)	76,452	(10,746)
Amortization of unrealized holding losses on held-to-maturity securities
Pre-tax Amount
Reclassification of net losses (gains) to net income, Pre-tax Amount	13,922	11,434	35,747	36,206
Income Tax Benefit (Expense)
Reclassification of net (losses) gains to net income, Income Tax Benefit (Expense)	(3,714)	(3,050)	(9,535)	(9,658)
Net of tax
Reclassification of net gains (losses) to net income, Net of tax	10,208	8,384	26,212	26,548
Cash flow derivative hedges
Pre-tax Amount
Unrealized net gains (losses) arising during the period, Pre-tax Amount	501	(373)	(325)	(2,868)
Reclassification of net losses (gains) to net income, Pre-tax Amount	7	1,723	1,825	4,599
Other comprehensive income , Pre-tax Amount	508	1,350	1,500	1,731
Income Tax Benefit (Expense)
Unrealized net gains (losses) arising during the period, Income Tax Benefit (Expense)	(133)	100	87	765
Reclassification of net (losses) gains to net income, Income Tax Benefit (Expense)	(2)	(460)	(487)	(1,227)
Other comprehensive loss, Income Tax Benefit (Expense)	(135)	(360)	(400)	(462)
Net of tax
Balance	(76)	(4,423)	(803)	(4,702)
Unrealized net gains (losses) arising during the period, Net of tax	368	(273)	(238)	(2,103)
Reclassification of net gains (losses) to net income, Net of tax	5	1,263	1,338	3,372
Other comprehensive income (loss)	373	990	1,100	1,269
Balance	$ 297	$ (3,433)	$ 297	$ (3,433)