Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 9,130	$ 20,919	$ 29,517	$ 64,282
Other comprehensive income (loss), net of tax:
Unrealized loss on debt securities available for sale	(20,217)	(47,155)	(3,984)	(142,643)
Accretion of unrealized (loss) on debt securities reclassified as held to maturity	(1)	(13)	(9)	(21)
Reclassification adjustment for (loss) gain included in net income	0	0	(7,779)	151
Total other comprehensive (loss) income, net of tax	(20,218)	(47,168)	(11,772)	(142,513)
Derivatives, net of tax:
Unrealized gain on swap contracts accounted for as cash flow hedges	1,845	1,182	3,863	5,167
Total derivative, net of tax	1,845	1,182	3,863	5,167
Employee benefit plans, net of tax:
Amortization of prior service cost included in net income	(10)	(11)	(30)	(31)
Reclassification adjustment of actuarial net gain (loss) included in net income	1	(244)	2	(732)
Change in funded status of retirement obligations	15	937	2,695	(17,121)
Total employee benefit plans, net of tax	6	682	2,667	(17,884)
Total other comprehensive (loss)	(18,367)	(45,304)	(5,242)	(155,230)
Total comprehensive (loss) income, net of tax	$ (9,237)	$ (24,385)	$ 24,275	$ (90,948)