Employee Retirement Plans (Schedule of Defined Benefit Plan, Amounts Recognized in Consolidated Financial Statements) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan [Abstract]
Accrued pension liability: Current portion	$ 327	$ 360
Accrued pension liability: Long term portion	743	1,016
Pre-tax accumulated other comprehensive income – retirement benefit liability adjustment	171	197
Net amount recognized	$ 1,241	$ 1,573