Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Service cost - benefits earned during the period	$ 33	$ 32	$ 62	$ 59
Interest cost	379	403	766	838
Expected return on plan assets	(556)	(730)	(659)	(1,405)
Amortization of net (gain)/loss	51	54	103	105
Net periodic pension (income)/cost	(93)	(241)	272	(403)
Pension Plan [Member]
Service cost - benefits earned during the period
Interest cost	326	350	656	725
Expected return on plan assets	(556)	(730)	(659)	(1,405)
Amortization of net (gain)/loss	59	62	119	122
Net periodic pension (income)/cost	(171)	(318)	116	(558)
SERP [Member]
Service cost - benefits earned during the period	33	32	62	59
Interest cost	53	53	110	113
Expected return on plan assets
Amortization of net (gain)/loss	(8)	(8)	(16)	(17)
Net periodic pension (income)/cost	$ 78	$ 77	$ 156	$ 155