Shareholders' Equity - Net Change in Components of Accumulated Other Comprehensive Income (Loss) and the Related Tax Effects (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax amount	$ 46,608	$ (9,908)
Other Comprehensive Income (Loss), Tax, Total	(11,651)	2,477
Other comprehensive income (loss), before reclassifications, net of tax amount	32,928	(11,138)
Reclassification from accumulated other comprehensive income, current period, net of tax amount	2,029	3,707
Other comprehensive income (loss), net of tax amount	34,957	(7,431)
Securities Available for Sale and Transferred Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax amount	32,599	(2,552)
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, before tax amount	3,425	3,661
Other comprehensive income (loss), before tax amount	36,024	1,109
Other comprehensive income (loss), before reclassifications, tax (expense) benefit	(8,149)	638
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, tax (expense) benefit	(856)	(915)
Other Comprehensive Income (Loss), Tax, Total	(9,005)	(277)
Other comprehensive income (loss), before reclassifications, net of tax amount	24,450	(1,914)
Other comprehensive income (loss), change in net unrealized holding loss on securities transferred to held to maturity, net of tax amount	2,569	2,746
Other comprehensive income (loss), net of tax amount	27,019	832
Net Change in Prior Service Costs [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, current period, before tax amount	4	28
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit	(1)	(7)
Reclassification from accumulated other comprehensive income, current period, net of tax amount	3	21
Recognized Net Loss Due to Lump Sum Settlements [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, current period, before tax amount	(50)	0
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit	12	0
Reclassification from accumulated other comprehensive income, current period, net of tax amount	(38)	0
Change in Net Actuarial Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, current period, before tax amount	71	95
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit	(17)	(24)
Reclassification from accumulated other comprehensive income, current period, net of tax amount	54	71
Pension and Other Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, current period, before tax amount	25	123
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit	(6)	(31)
Reclassification from accumulated other comprehensive income, current period, net of tax amount	19	92
Cash Flow Hedge Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, before tax amount	7,879	(15,960)
Reclassification from accumulated other comprehensive income, current period, before tax amount	2,680	4,820
Other comprehensive income (loss), before tax amount	10,559	(11,140)
Other comprehensive income (loss), before reclassifications, tax (expense) benefit	(1,970)	3,990
Reclassification from accumulated other comprehensive income, current period, tax (expense) benefit	(670)	(1,205)
Other Comprehensive Income (Loss), Tax, Total	(2,640)	2,785
Other comprehensive income (loss), before reclassifications, net of tax amount	5,909	(11,970)
Reclassification from accumulated other comprehensive income, current period, net of tax amount	2,010	3,615
Other comprehensive income (loss), net of tax amount	$ 7,919	$ (8,355)