Components of Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Average daily balance during the year
Interest cost	$ 119	$ 128
Expected return on plan assets	(160)	(136)
Net amortization	103	102
Total periodic pension expense	62	94
Amortization of actuarial loss	(101)	(101)
Total recognized in other comprehensive income	(101)	(101)
Total recognized in net periodic expense and other comprehensive income (before tax)	$ (39)	$ (7)