Pension - Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Components of net periodic benefit cost:
Interest cost	$ 15	$ 15	$ 44	$ 44
Service cost	6	6	19	19
Expected return on plan assets	(23)	(24)	(69)	(70)
Amortization of prior service costs	2	2	7	7
Amortization of actuarial loss	28	36	84	92
Net periodic benefit cost	$ 28	$ 35	$ 85	$ 92