Equipment and Leasehold Improvements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements	$ 38,104	$ 38,713
Less accumulated depreciation and amortization	28,265	28,383
Property, Plant and Equipment, Net, Total	9,839	10,330
Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements	36,465	37,074
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements	$ 1,639	$ 1,639