Fixed Assets (Schedule of Depreciation and Amortization of Fixed Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Cost of sales	$ 35,656	$ 27,042	$ 22,993
Selling, general and administrative expenses	10,608	7,798	5,140
Total	$ 46,264	$ 34,840	$ 28,133