Acquisition (Summary of Fair Values of Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Aug. 04, 2015
Business Acquisition [Line Items]
Goodwill	$ 55,947	$ 53,391
Fred Deeley Imports, Ltd.
Business Acquisition [Line Items]
Current assets			$ 11,088
Property, plant and equipment			144
Intangible assets			20,842
Goodwill			28,567
Total assets			60,641
Current liabilities			731
Net assets acquired			$ 59,910