Overview and significant Accounting Policies (Details 2) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) facility	Dec. 31, 2017 USD ($)
Geographic concentrations
Number of facilities to provide services | facility									23
Total revenue	$ 70,209	$ 63,588	$ 69,633	$ 81,198	$ 99,866	$ 94,424	$ 94,722	$ 94,894	$ 284,628	$ 383,906
Total property, plant and equipment	13,592				21,787				13,592	21,787
United States
Geographic concentrations
Total revenue									243,298	330,944
Total property, plant and equipment	11,647				18,789				$ 11,647	18,789
Other countries
Geographic concentrations
Number of facilities to provide services | facility									4
Total revenue									$ 41,330	52,962
Total property, plant and equipment	$ 1,945				$ 2,998				$ 1,945	$ 2,998