Securities, Held to Maturity (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	$ 890,863		$ 905,267
Unrealized gains	101		271
Unrealized losses	(97,645)		(91,014)
Estimated fair value	793,319		814,524
Transactions of HTM securities [Abstract]
Gains from calls on HTM securities	0	$ 0
Asset Pledged as Collateral [Member] \| Public Deposits or Other Purposes [Member]
Securities pledged [Abstract]
AFS and HTM securities	1,990,000		2,030,000
Asset Pledged as Collateral [Member] \| Securities Sold under Repurchase Agreements [Member]
Securities pledged [Abstract]
AFS and HTM securities	159,300		177,200
Federal Agency [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	100,000		100,000
Unrealized gains	0		0
Unrealized losses	(18,440)		(17,784)
Estimated fair value	81,560		82,216
Mortgage-Backed, Government Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	224,344		228,720
Unrealized gains	0		0
Unrealized losses	(34,187)		(31,613)
Estimated fair value	190,157		197,107
Mortgage-Backed, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	16,742		17,086
Unrealized gains	2		3
Unrealized losses	(736)		(566)
Estimated fair value	16,008		16,523
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	182,813		187,457
Unrealized gains	0		57
Unrealized losses	(13,466)		(12,021)
Estimated fair value	169,347		175,493
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	63,137		63,878
Unrealized gains	0		0
Unrealized losses	(11,206)		(10,908)
Estimated fair value	51,931		52,970
State & Municipal [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	303,827		308,126
Unrealized gains	99		211
Unrealized losses	(19,610)		(18,122)
Estimated fair value	$ 284,316		$ 290,215

Gains from calls (requests of early payments) on debt securities which are classified as held-to-maturity securities.

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Amount, after 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), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Amount, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Topic 320
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

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-Topic 320
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- Definition

Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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