Business Segments (Sales by Geographical Location) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets
Net Sales	$ 626,969	$ 536,377
United States
Revenues from External Customers and Long-Lived Assets
Net Sales	484,907	431,868
Canada
Revenues from External Customers and Long-Lived Assets
Net Sales	66,451	37,237
United Kingdom
Revenues from External Customers and Long-Lived Assets
Net Sales	42,810	38,859
Other
Revenues from External Customers and Long-Lived Assets
Net Sales	$ 32,801	$ 28,413