Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 22,959	$ 26,688	$ 43,363	$ 47,733
Other comprehensive (loss) income, net of tax:
Unrealized (loss) gain on debt securities available for sale	(37,676)	4,788	(95,491)	(12,246)
Accretion of unrealized (loss) gain on debt securities reclassified as held to maturity	(3)	(12)	(6)	2
Reclassification adjustment for gain included in net income	152	(202)	152	(202)
Total other comprehensive (loss) income, net of tax	(37,527)	4,574	(95,345)	(12,446)
Derivatives, net of tax:
Unrealized gain on swap contracts accounted for as cash flow hedges	828	948	3,985	6,631
Total derivative, net of tax	828	948	3,985	6,631
Employee benefit plans, net of tax:
Amortization of prior service cost included in net income	(11)	(11)	(22)	(20)
Reclassification adjustment of actuarial net (loss) included in net income	(244)	(1,089)	(488)	(2,178)
Change in funded status of retirement obligations	(18,536)	24,818	(18,056)	34,371
Total employee benefit plans, net of tax	(18,791)	23,718	(18,566)	32,173
Total other comprehensive (loss) income	(55,490)	29,240	(109,926)	26,358
Total comprehensive (loss) income, net of tax	$ (32,531)	$ 55,928	$ (66,563)	$ 74,091