Investment Securities - Schedule of Unrealized Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	$ 6,419,874	$ 5,794,884
Gross unrealized gains	57,171	7,432
Gross unrealized losses	(104,582)	(198,593)
Fair values	6,372,463	5,603,723
Held to maturity:
Amortized Cost	1,699	3,246
Gross unrealized gains	1	1
Gross unrealized losses	0	(16)
Fair values	1,700	3,231
Allowance for credit losses	(10)	(21)
Fair Value	1,690	3,210
U.S. Treasury securities
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	918,922	1,291,137
Gross unrealized gains	10,561	752
Gross unrealized losses	(1,196)	(22,336)
Fair values	928,287	1,269,553
U.S. government obligations and government-sponsored enterprises
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	132,692	373,869
Gross unrealized gains	177	54
Gross unrealized losses	(413)	(4,635)
Fair values	132,456	369,288
U.S. Agency mortgage-backed securities
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	5,345,130	4,078,956
Gross unrealized gains	46,346	6,535
Gross unrealized losses	(102,899)	(170,739)
Fair values	5,288,577	3,914,752
Held to maturity:
Amortized Cost	21	25
Gross unrealized gains	1	1
Gross unrealized losses	0	0
Fair values	22	26
Allowance for credit losses	0	0
Fair Value	22	26
Obligations of states and political subdivisions
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	16,595	21,274
Gross unrealized gains	87	79
Gross unrealized losses	(38)	(212)
Fair values	16,644	21,141
Held to maturity:
Amortized Cost	1,678	3,221
Gross unrealized gains	0	0
Gross unrealized losses	0	(16)
Fair values	1,678	3,205
Allowance for credit losses	(10)	(21)
Fair Value	1,668	3,184
Other securities
Debt Securities, Available-for-Sale [Abstract]
Amortized cost	6,535	29,648
Gross unrealized gains	0	12
Gross unrealized losses	(36)	(671)
Fair values	6,499	$ 28,989
Held to maturity:
Fair values	$ 0

Debt Securities, Held-to-Maturity, Fair Value, Before Allowance For Credit Loss

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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