Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, beginning balance	$ 19,995	$ 19,009
Goodwill, acquired	23,188	1,720
Goodwill, effects of foreign currency	437	(734)
Goodwill, ending balance	43,620	19,995
Fluids systems [Member]
Goodwill [Line Items]
Goodwill, beginning balance	1,666	0
Goodwill, acquired	0	1,720
Goodwill, effects of foreign currency	116	(54)
Goodwill, ending balance	1,782	1,666
Mats and integrated services [Member]
Goodwill [Line Items]
Goodwill, beginning balance	18,329	19,009
Goodwill, acquired	23,188	0
Goodwill, effects of foreign currency	321	(680)
Goodwill, ending balance	$ 41,838	$ 18,329