Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Allowance for loan losses	$ 17,486	$ 20,878
Post-retirement benefits	5,974	5,544
Deferred compensation	3,519	2,779
Retirement Income Maintenance plan	2,767	2,471
ESOP	810	624
Stock-based compensation	2,288	1,699
Reserve for uncollected interest	28	126
Net unrealized losses on debt securities and defined benefit plans	17,809	18,511
Federal and State NOLs	9,667	9,719
Alternative minimum assessment carryforwards	2,156	2,156
Charitable contribution carryforward	4,529	6,359
Purchase accounting	1,551	1,024
Lease liability	5,462	5,609
Other items	4,077	3,215
Gross deferred tax assets	78,123	80,714
Valuation allowance	(1,965)	(2,002)
Total deferred tax assets, net	76,158	78,712
Deferred tax liabilities:
Pension expense	61,530	49,225
Depreciation	6,655	6,118
Deferred loan costs	10,630	8,555
Intangible assets	1,594	1,597
Lease right-of-use asset	5,191	5,317
Other items	307	716
Total gross deferred tax liabilities	85,907	71,528
Net deferred tax (liability) asset		$ 7,184
Net deferred tax (liability) asset	$ (9,749)