Pension - Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Components of net periodic benefit cost:
Interest cost	$ 15	$ 15	$ 29	$ 29
Service cost	6	6	13	13
Expected return on plan assets	(23)	(23)	(46)	(46)
Amortization of prior service costs	2	2	5	5
Amortization of actuarial loss	28	28	56	56
Net periodic benefit cost	$ 28	$ 28	$ 57	$ 57