Comprehensive Income - Changes in Accumulated Other Comprehensive Income By Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	$ 334,392	$ 301,728
Other comprehensive income or loss before reclassifications	(2,337)	3,879
Amounts reclassified from accumulated other comprehensive income	57	66
Other Comprehensive (Loss) Income	(2,280)	3,945
Stockholders' equity, ending balance	342,413	309,398
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(816)	(6,357)
Stockholders' equity, ending balance	(3,096)	(2,412)
Unrealized Gains and Losses on Available for Sale Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	5,799	465
Other comprehensive income or loss before reclassifications	(3,812)	4,098
Amounts reclassified from accumulated other comprehensive income	0	0
Other Comprehensive (Loss) Income	(3,812)	4,098
Stockholders' equity, ending balance	1,987	4,563
Unrealized Loss on Cash Flow Swap
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	485	0
Other comprehensive income or loss before reclassifications	1,475	(219)
Amounts reclassified from accumulated other comprehensive income	(20)	0
Other Comprehensive (Loss) Income	1,455	(219)
Stockholders' equity, ending balance	1,940	(219)
Net Actuarial Gain (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(5,929)	(5,847)
Other comprehensive income or loss before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	34	27
Other Comprehensive (Loss) Income	34	27
Stockholders' equity, ending balance	(5,895)	(5,820)
Net Prior Service (Cost) Credit
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(1,171)	(975)
Other comprehensive income or loss before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive income	43	39
Other Comprehensive (Loss) Income	43	39
Stockholders' equity, ending balance	$ (1,128)	$ (936)