Other Comprehensive Income - Summary of Change in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 304,966	$ 262,830	$ 243,910
Comprehensive Income (Loss)	8,135	10,935	(3,653)
Ending balance	416,137	304,966	262,830
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	6,939	(3,996)	(343)
Comprehensive Income (Loss)	8,135	10,935	(3,653)
Reclassification of Disproportionate Tax Effect	0	0	0
Ending balance	15,074	6,939	(3,996)
Unrealized gains (losses) on securities available for sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	7,198	(3,534)	473
Comprehensive Income (Loss)	8,140	10,732	(4,007)
Reclassification of Disproportionate Tax Effect	0	0	0
Ending balance	15,338	7,198	(3,534)
Unrealized gain (loss) on postretirement benefits plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	124	(304)	(690)
Comprehensive Income (Loss)	219	428	386
Reclassification of Disproportionate Tax Effect	0	0	0
Ending balance	343	124	(304)
Unrealized loss on interest rate swap
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(383)	(158)	(126)
Comprehensive Income (Loss)	(224)	(225)	(32)
Reclassification of Disproportionate Tax Effect	0	0	0
Ending balance	$ (607)	$ (383)	$ (158)