TAX EFFECT ALLOCATED TO EACH COMPONENT OF OTHER COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Statement of Income and Comprehensive Income
Adjustment of pension and postretirement benefit plans	$ 0	$ 0	$ 0	$ 0
Amortization of net losses of pension and postretirement benefit plans	(1,357)	(1,805)	(2,714)	(3,610)
Unrealized holding (losses) gains on debt securities arising during the period	(5,481)	7,910	(3,555)	(13,656)
Amortization of unrealized losses of debt securities transfer from available-for-sale to held-to-maturity	(8,884)	(8,581)	(17,685)	(16,988)
Unrealized net (losses) gains on cash flow hedges	0	0	0	11
Reclassification adjustment for net (gains) losses included in net income	0	0	0	15
Income tax expense	$ (15,722)	$ (2,476)	$ (23,954)	$ (34,228)

Amount of tax expense (benefit) on adjustment from accumulated other comprehensive income (loss) for amortization of gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale) from transfer to investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
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-Paragraph 10B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481889/320-10-35-10B

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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Tax effect of plan amendments that occurred that has not been recognized in net periodic benefit cost.

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