Accumulated Comprehensive Loss (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance				$ 129,011
Change in Accounting policy for equity securities		$ 1		1
Other comprehensive income (loss) before reclassifications (net of tax)		(417)	$ 432	(2,034)	$ 478
Amounts reclassified from accumulated other comprehensive income (loss) (net of tax)		37	20	74	(55)
Other comprehensive income (loss), net of tax		(380)	452	(1,960)	423
Ending Balance		132,281		132,281
Accumulated Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(4,977)	(1,421)	(3,398)	(1,392)
Ending Balance		(5,357)	(969)	(5,357)	(969)
Unrealized Gain (Loss) on Available for Sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	[1]	(1,885)	1,238	(269)	1,306
Change in Accounting policy for equity securities	[1]	1		1
Other comprehensive income (loss) before reclassifications (net of tax)	[1]	(417)	432	(2,034)	478
Amounts reclassified from accumulated other comprehensive income (loss) (net of tax)	[1]	0	(15)	0	(129)
Other comprehensive income (loss), net of tax	[1]	(417)	417	(2,034)	349
Ending Balance	[1]	(2,302)	1,655	(2,302)	1,655
Defined Benefit Pension Items [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	[1]	(3,092)	(2,659)	(3,129)	(2,698)
Change in Accounting policy for equity securities	[1]	0		0
Other comprehensive income (loss) before reclassifications (net of tax)	[1]	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss) (net of tax)	[1]	37	35	74	74
Other comprehensive income (loss), net of tax	[1]	37	35	74	74
Ending Balance	[1]	$ (3,055)	$ (2,624)	$ (3,055)	$ (2,624)

[1] Amounts in parentheses indicate debits on the Consolidated Balance Sheet.