Other Comprehensive Income (Loss) - Accumulated Balances for Each Component of Other Comprehensive Income (Loss), Net of Tax (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accumulated balances for component of other comprehensive income, net of tax
Unrealized losses on securities	$ (198,769)	$ (219,766)
Unrealized gains on derivative instruments	15,363	18,956
Unrecognized losses on defined benefit pension and post-retirement benefit plans obligations	(8,055)	(8,227)
Total accumulated other comprehensive loss	$ (191,461)	$ (209,037)

Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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- Definition

Amount, after tax, of accumulated increase (decrease) in equity from transaction and other event and circumstance from nonowner source.

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Amount, after tax, of accumulated gain (loss) on derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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