Pension Plan (Details) - Components of net periodic pension cost - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Components of net periodic pension cost [Abstract]
Interest cost	$ 116	$ 120
Expected return on plan assets	(179)	(168)
Amortization of net actuarial loss	54	48
Net periodic pension cost	$ (9)