Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 20,919	$ 20,982	$ 64,282	$ 68,715
Other comprehensive (loss) income, net of tax:
Unrealized (loss) on debt securities available for sale	(47,155)	(9,943)	(142,643)	(22,189)
Accretion of unrealized (loss) on debt securities reclassified as held to maturity	(13)	(2)	(21)	0
Reclassification adjustment for gain included in net income	0	1,791	151	1,589
Total other comprehensive (loss) income, net of tax	(47,168)	(8,154)	(142,513)	(20,600)
Derivatives, net of tax:
Unrealized gain on swap contracts accounted for as cash flow hedges	1,182	1,467	5,167	8,098
Total derivative, net of tax	1,182	1,467	5,167	8,098
Employee benefit plans, net of tax:
Amortization of prior service cost included in net income	(11)	(10)	(31)	(31)
Reclassification adjustment of actuarial net (loss) included in net income	(244)	(1,089)	(732)	(3,267)
Change in funded status of retirement obligations	937	2,198	(17,121)	36,570
Total employee benefit plans, net of tax	682	1,099	(17,884)	33,272
Total other comprehensive (loss) income	(45,304)	(5,588)	(155,230)	20,770
Total comprehensive (loss) income, net of tax	$ (24,385)	$ 15,394	$ (90,948)	$ 89,485