Comprehensive Income - Changes in Accumulated Other Comprehensive Income By Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	$ 317,687	$ 284,649	$ 301,728	$ 269,584
Other comprehensive income or loss before reclassifications	(58)	499	5,860	4,323
Amounts reclassified from accumulated other comprehensive income	81	169	244	508
Other Comprehensive Income	23	668	6,104	4,831
Stockholders' equity, ending balance	325,660	292,228	325,660	292,228
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(276)	(9,647)	(6,357)	(13,810)
Stockholders' equity, ending balance	(253)	(8,979)	(253)	(8,979)
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	6,584	127	465	(3,697)
Other comprehensive income or loss before reclassifications	(296)	499		4,323
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income	(296)	499	5,823	4,323
Stockholders' equity, ending balance	6,288	626	6,288	626
Unrealized Loss on Cash Flow Swap
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(201)	0	0	0
Other comprehensive income or loss before reclassifications	238	0	37	0
Amounts reclassified from accumulated other comprehensive income	0	0	0	0
Other Comprehensive Income	238	0	37	0
Stockholders' equity, ending balance	37	0	37	0
Net Actuarial Gain (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(5,762)	(8,717)	(5,847)	(8,971)
Other comprehensive income or loss before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	42	127	127	381
Other Comprehensive Income	42	127	127	381
Stockholders' equity, ending balance	(5,720)	(8,590)	(5,720)	(8,590)
Net Priot Service (Cost) Credit
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(897)	(1,057)	(975)	(1,142)
Other comprehensive income or loss before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	39	42	117	127
Other Comprehensive Income	39	42	117	127
Stockholders' equity, ending balance	$ (858)	$ (1,015)	$ (858)	$ (1,015)