Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 1,664	$ 22,959	$ 20,387	$ 43,363
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on debt securities available for sale	3,165	(37,676)	16,234	(95,491)
Accretion of unrealized (loss) on debt securities reclassified as held to maturity	(1)	(3)	(9)	(6)
Reclassification adjustment for (loss) gain included in net income	(6,851)	152	(7,779)	152
Total other comprehensive (loss) income, net of tax	(3,687)	(37,527)	8,446	(95,345)
Derivatives, net of tax:
Unrealized gain on swap contracts accounted for as cash flow hedges	2,883	828	2,018	3,985
Total derivative, net of tax	2,883	828	2,018	3,985
Employee benefit plans, net of tax:
Amortization of prior service cost included in net income	(10)	(11)	(20)	(22)
Reclassification adjustment of actuarial net gain (loss) included in net income	1	(244)	1	(488)
Change in funded status of retirement obligations	2,500	(18,536)	2,680	(18,056)
Total employee benefit plans, net of tax	2,491	(18,791)	2,661	(18,566)
Total other comprehensive income (loss)	1,687	(55,490)	13,125	(109,926)
Total comprehensive income (loss), net of tax	$ 3,351	$ (32,531)	$ 33,512	$ (66,563)