Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities:
Unrealized holdings losses, pre-tax amount	$ (161,269)	$ (38,832)	$ 33,198
Unrealized holdings losses, tax (expense) benefit	34,673	8,349	(7,138)
Unrealized holdings losses, after-tax amount	(126,596)	(30,483)	26,060
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, before tax	5,715	0	0
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, tax	(1,229)	0	0
Less: reclassification adjustment for amortization of securities transferred from AFS to HTM, after tax	4,486	0	0
Less: reclassification adjustment for realized losses, pre-tax amount	(912)
Less: reclassification adjustment for realized losses, tax (expense) benefit	196
Less: reclassification adjustment for realized losses, after-tax amount	(716)
Net unrealized losses, pre-tax amount	(166,072)	(38,832)	33,198
Net unrealized losses, tax (expense) benefit	35,706	8,349	(7,138)
Net unrealized losses, after-tax amount	(130,366)	(30,483)	26,060
Cash Flow Hedges:
Net increase in fair value, pre-tax amount	10,038	2,987	1,214
Net increase in fair value, tax (expense) benefit	(2,158)	(642)	(260)
Net increase in fair value, after-tax amount	7,880	2,345	954
Net increase in fair value, pre-tax amount	9,770	3,627	1,811
Net increase in fair value, tax (expense) benefit	(2,100)	(780)	(389)
Net increase in fair value, after-tax amount	7,670	2,847	1,422
Postretirement Plans:
Net actuarial loss, pre-tax amount	2,859	(20)	(1,282)
Net actuarial loss, tax (expense) benefit	(614)	4	277
Net actuarial loss, after-tax amount	2,245	(16)	(1,005)
Less: Amortization of net actuarial losses, pre-tax amount	(947)	(894)	(701)
Less: Amortization of net actuarial losses, tax (expense) benefit	203	192	151
Less: Amortization of net prior service credits, after-tax amount	(744)	(702)	(550)
Less: Amortization of net prior service credits, pre-tax amount	24	24	24
Less: Amortization of net prior service credits, tax (expense) benefit	(5)	(5)	(5)
Less: Amortization of net prior service credits, after-tax amount	19	19	19
Net loss on postretirement plans, pre-tax amount	3,782	850	(605)
Net loss on postretirement plans, tax (expense) benefit	(812)	(183)	131
Net (loss) gain on postretirement plans, net of tax	2,970	667	(474)
Other comprehensive income, pre-tax amount	(152,520)	(34,355)	34,404
Other comprehensive income, tax (expense) benefit	32,794	7,386	(7,396)
Other comprehensive (loss) income	(119,726)	(26,969)	27,008
Interest Expense, Borrowings and Subordinated Debentures
Cash Flow Hedges:
Less: effective portion reclassified into interest expense, pre-tax amount	263	(2,254)	(1,603)
Less: effective portion reclassified into interest expense, tax (expense) benefit	(57)	485	345
Less: effective portion reclassified into interest expense, after-tax amount	206	(1,769)	(1,258)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Less: effective portion reclassified into interest expense, pre-tax amount	263	(2,254)	(1,603)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	57	(485)	(345)
Less: Amounts reclassified from AOCI	206	(1,769)	(1,258)
Interest Income, Interest and Fees on Loans
Cash Flow Hedges:
Less: effective portion reclassified into interest expense, pre-tax amount	5	1,614	1,006
Less: effective portion reclassified into interest expense, tax (expense) benefit	(1)	(347)	(216)
Less: effective portion reclassified into interest expense, after-tax amount	4	1,267	790
Accumulated Other Comprehensive Income (Loss) [Line Items]
Less: effective portion reclassified into interest expense, pre-tax amount	5	1,614	1,006
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	1	347	216
Less: Amounts reclassified from AOCI	$ 4	$ 1,267	$ 790