Goodwill and Other Intangibles - Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Balance at the beginning of the period	$ 10,102
Balance at the end of the period	11,054	$ 10,102
European Operations | Operating Segments
Goodwill
Balance at the beginning of the period	10,102	11,933
Currency translation adjustment	952	(1,831)
Balance at the end of the period	$ 11,054	$ 10,102