Reclassification Adjustments Out of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of AOCI [Abstract]
Net securities (gains) losses	$ 476	$ (183)	$ 2,567	$ (9,822)
Interest income	101,669	94,895	294,017	279,046
Other noninterest expense	6,112	6,514	17,865	17,284
Income tax (benefit)	10,681	7,095	29,275	25,339
Net income	38,097	24,606	104,636	88,336
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Total reclassifications, net of tax	419	565	1,986	8,792
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Income tax (benefit)	(21)	(26)	(68)	(2,445)
Net income	66	79	206	7,333
Losses on AFS Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Net securities (gains) losses			0	9,450
Amortization of Unrealized Gains Related to Securities Transfer [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Interest income	87	105	274	328
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Income tax (benefit)	(118)	(162)	(594)	(487)
Net income	353	486	1,780	1,459
Amortization of Net Losses [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Other noninterest expense	474	638	2,382	1,918
Amortization of Prior Service Costs [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of AOCI [Abstract]
Other noninterest expense	$ (3)	$ 10	$ (8)	$ 28