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Investment Securities - Amortized Cost and Fair Value of Available-for-Sale Investment Securities Portfolio (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Available-for-Sale
Amortized Cost	$ 12,059,997	$ 8,480,508
Unrealized Gains	83,904	6,987
Unrealized Losses	(654,333)	(897,516)
Basis Adjustments	(105,118)	(131,520)
Fair Value	11,384,450	7,458,459
U.S. Treasury
Available-for-Sale
Amortized Cost	269,313	261,421
Unrealized Gains	90	67
Unrealized Losses	(7,615)	(12,659)
Basis Adjustments	(47,244)	(49,816)
Fair Value	214,544	199,013
U.S. government-sponsored entities and agencies
Available-for-Sale
Amortized Cost	1,567,036	1,521,610
Unrealized Gains	402	7
Unrealized Losses	(134,795)	(181,360)
Basis Adjustments	(60,251)	(82,351)
Fair Value	1,372,392	1,257,906
Mortgage-backed securities
Available-for-Sale
Amortized Cost	9,575,241	5,861,067
Unrealized Gains	79,999	6,005
Unrealized Losses	(487,205)	(662,181)
Basis Adjustments	0	0
Fair Value	9,168,035	5,204,891
States and political subdivisions
Available-for-Sale
Amortized Cost	438,642	510,630
Unrealized Gains	2,275	148
Unrealized Losses	(17,286)	(25,881)
Basis Adjustments	2,377	647
Fair Value	426,008	485,544
Pooled trust preferred securities
Available-for-Sale
Amortized Cost	13,819	13,807
Unrealized Gains	0	0
Unrealized Losses	(2,085)	(2,485)
Basis Adjustments	0	0
Fair Value	11,734	11,322
Other securities
Available-for-Sale
Amortized Cost	195,946	311,973
Unrealized Gains	1,138	760
Unrealized Losses	(5,347)	(12,950)
Basis Adjustments	0	0
Fair Value	$ 191,737	$ 299,783

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- Definition

Debt Securities, Available-For-Sale, Accumulated Basis Adjustments, Before Tax

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- Definition

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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- Definition

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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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- Definition

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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