Business Acquisitions (Details textual) - USD ($)		6 Months Ended
	Nov. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 920,364,000	$ 801,406,000
Goodwill, Acquired During Period		100,022,000
Prox Dynamics, AS [Member]
Business Acquisition [Line Items]
Cash acquired		11,706,000
Goodwill	$ 91,900,000
Total purchase price	134,088,000
Identifiable intangible assets	31,400,000	31,400,000
Prox Dynamics [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	11.3
Goodwill		$ 99,300,000
Total purchase price	134,088,000
Intangible assets including goodwill	$ 122.8