Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets [Abstract]
Restricted Insurance Settlement	$ 21,171	$ 21,883
Uncertain Tax Positions	4,543	3,892
Supplemental Retirement Income Program	1,594	1,410
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	1,184	0
Other	1,557	1,567
Total	$ 30,049	$ 28,752