Pension Plan (Details) - Presentation of the non-service components of periodic pension cost to Pension benefit - Accounting Standards Update 2017-07 [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
General and administrative expenses	$ 6,613
Operating loss	(2,881)
Pension benefit	(35)
Loss before income taxes	(2,849)
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
General and administrative expenses	6,578
Operating loss	(2,846)
Pension benefit
Loss before income taxes	(2,849)
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
General and administrative expenses	35
Operating loss	(35)
Pension benefit	(35)
Loss before income taxes