Business Segments (Long Lived Asset by Geography) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets
Long-lived assets	$ 96,096	$ 103,973	$ 126,745
United States
Revenues from External Customers and Long-Lived Assets
Long-lived assets	89,439	96,650	118,053
Canada
Revenues from External Customers and Long-Lived Assets
Long-lived assets	4,788	5,445	6,186
United Kingdom
Revenues from External Customers and Long-Lived Assets
Long-lived assets	1,850	1,842	2,449
Other
Revenues from External Customers and Long-Lived Assets
Long-lived assets	$ 19	$ 36	$ 57