Accumulated Other Comprehensive (Loss) Income - Changes in 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
Equity [Abstract]
Unrealized loss on securities, before tax amount	$ 88,637	$ (135,811)	$ 48,735	$ (133,973)
Unrealized loss on securities, tax effect	(20,077)	30,761	(11,039)	30,345
Unrealized loss on securities, net of tax amount	68,560	(105,050)	37,696	(103,628)
Reclassification adjustment for securities gain included in net income, before tax amount	1	0	20,283	19
Reclassification adjustment for securities gain included in net income, tax effect	0	0	(4,594)	(5)
Reclassification adjustment for securities gain included in net income, net of tax amount	1	0	15,689	14
Amortization of net unrealized losses on AFS securities transferred to HTM. before-tax amount	1,837	1,932	5,445	5,783
Amortization of net unrealized losses on AFS securities transferred to HTM, tax	(415)	(438)	(1,233)	(1,310)
Amortization of net unrealized losses on AFS securities transferred to HTM, net of tax amount	1,422	1,494	4,212	4,473
Net unrealized loss on interest rate swaps used in cash flow hedges, before-tax amount	(8,564)	4,691	(92)	9,975
Net unrealized loss on interest rate swaps used in cash flow hedges, before-tax amount	1,940	(1,040)	21	(18,730)
Amount of Gain (Loss) Recognized in OCI on Derivative	(6,624)	3,651	(71)	(8,755)
Net unrealized losses on interest rate swaps used in cash flow hedges, before-tax amount	5,144	6,248	15,158	20,437
Net unrealized losses on interest rate swaps used in cash flow hedges, tax	(1,165)	172	(3,389)	136
Net unrealized losses on interest rate swaps used in cash flow hedges, net of tax amount	3,979	6,420	11,769	20,573
Amortization of net unrecognized pension and postretirement items, before tax amount	(135)	18	(406)	55
Amortization of net unrecognized pension and postretirement items, tax effect	29	(3)	89	(12)
Amortization of net unrecognized pension and postretirement items, net of tax amount	(106)	15	(317)	43
Total Other Comprehensive Income, Before Tax Amount	86,920	(122,922)	89,123	(97,704)
Total Other Comprehensive Income, Tax Effect	(19,688)	29,452	(20,145)	10,424
Other Comprehensive Income (Loss), net of tax	$ 67,232	$ (93,470)	$ 68,978	$ (87,280)