Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 127,528	$ 118,396
Balance	129,005	121,491
Unrealized Gains And Losses On Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	185	(870)
Other comprehensive income before reclassification	1,618	1,117
Amounts reclassified from accumulated other comprehensive income	(8)	(18)
Current period other comprehensive income	1,626	1,099
Balance	1,811	229
Defined Benefit Pension Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(6,171)	(5,510)
Other comprehensive income before reclassification
Amounts reclassified from accumulated other comprehensive income
Current period other comprehensive income
Balance	(6,171)	(5,510)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(5,986)	(6,380)
Other comprehensive income before reclassification	1,618	1,117
Amounts reclassified from accumulated other comprehensive income	(8)	(18)
Current period other comprehensive income	1,626	1,099
Balance	$ (4,360)	$ (5,281)