Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 127,528	$ 118,396
Balance	134,840	123,914
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	5,253	2,082
Amounts reclassified from accumulated other comprehensive income	(8)	(200)
Current period other comprehensive income	5,261	1,882
Balance	5,446	1,012
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	5,253	2,082
Amounts reclassified from accumulated other comprehensive income	(8)	(200)
Current period other comprehensive income	5,261	1,882
Balance	$ (725)	$ (4,498)