Intangible Assets Intangible (Details textual ) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Nov. 30, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles			$ 123,100
Disposal Group, Including Discontinued Operation, Assets, Current	$ 67,344	$ 0
Prox Dynamics, AS [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles			$ 31,400