Acquisitions (Details 1) - USD ($) $ in Thousands	Jun. 30, 2018	May 31, 2018	May 29, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 413,837			$ 401,758
Altek
Business Acquisition [Line Items]
Cash and cash equivalents			$ 1,700
Net working capital			(1,500)
Property, plant and equipment, net			3,300
Intangible assets			52,500
Goodwill			20,900
Net deferred tax liabilities			(8,500)
Other liabilities			(300)
Total identifiable net assets of Altek			$ 68,200
Goodwill to be deductible for tax purposes (less than $1.0 million)		$ 1,000