Employee Benefit Plans (Amounts Recognized in Consolidated Balance Sheets) (Details) - Employee Pension Plans [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Funded Status
Funded status	$ (34,677)	$ (37,624)
Net unfunded amounts recognized in Consolidated Balance Sheets consist of:
Current liabilities	(279)	(271)
Long-term liabilities	(34,398)	(37,353)
Total net unfunded amount recognized in Consolidated Balance Sheets	$ (34,677)	$ (37,624)