Securities, Held to Maturity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	$ 914,520		$ 914,520		$ 919,517
Unrealized gains	0		0		209
Unrealized losses	(130,534)		(130,534)		(107,079)
Estimated fair value	783,986		783,986		812,647
Allowance for credit losses on HTM securities	0		0		0
Transactions of HTM securities [Abstract]
Gains from calls on HTM securities	0	$ 0	0	$ 4
Asset Pledged as Collateral [Member] | Public Deposits or Other Purposes [Member]
Securities pledged [Abstract]
AFS and HTM securities	1,990,000		1,990,000		1,730,000
Asset Pledged as Collateral [Member] | Securities Sold under Repurchase Agreements [Member]
Securities pledged [Abstract]
AFS and HTM securities	157,400		157,400		149,500
Federal Agency [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	100,000		100,000		100,000
Unrealized gains	0		0		0
Unrealized losses	(23,003)		(23,003)		(20,678)
Estimated fair value	76,997		76,997		79,322
Mortgage-Backed, Government Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	233,580		233,580		249,511
Unrealized gains	0		0		0
Unrealized losses	(45,066)		(45,066)		(36,819)
Estimated fair value	188,514		188,514		212,692
Mortgage-Backed, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	17,094		17,094		18,396
Unrealized gains	0		0		4
Unrealized losses	(1,328)		(1,328)		(619)
Estimated fair value	15,766		15,766		17,781
Collateralized Mortgage Obligations, Government-Sponsored Enterprises [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	192,243		192,243		207,738
Unrealized gains	0		0		200
Unrealized losses	(18,562)		(18,562)		(14,876)
Estimated fair value	173,681		173,681		193,062
Collateralized Mortgage Obligations, U.S. Government Agency Securities [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	64,537		64,537		66,628
Unrealized gains	0		0		0
Unrealized losses	(13,259)		(13,259)		(9,842)
Estimated fair value	51,278		51,278		56,786
State & Municipal [Member]
Held-to-maturity securities, fair value to amortized cost [Abstract]
Amortized cost	307,066		307,066		277,244
Unrealized gains	0		0		5
Unrealized losses	(29,316)		(29,316)		(24,245)
Estimated fair value	$ 277,750		$ 277,750		$ 253,004