Acquisitions (Narrative) (Details) $ in Thousands		3 Months Ended	12 Months Ended
	Oct. 23, 2015 USD ($) shares	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) item
Business Acquisition [Line Items]
Decrease in goodwill			$ 1,585
Micropross [Member]
Business Acquisition [Line Items]
Date of acquisition			Oct. 23, 2015
Cash paid for acquired company	$ 89,000
Combined purchase price of acquisitions	99,000
Common stock paid for acquired company	$ 10,400
Common stock shares paid for acquired company | shares	367,481
Borrowings assumed from acquired entity	$ 5,000
Micropross [Member] | Acquisition-related Costs [Member]
Business Acquisition [Line Items]
Net Identifiable Assets		$ 1,600
Micropross [Member] | Write Down to Fair Value of Acquired Deferred Revenue [Member]
Business Acquisition [Line Items]
Revenues		900
Micropross [Member] | Fair Value Adjustment to Inventory [Member]
Business Acquisition [Line Items]
Revenues		700
Other Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired | item			4
Cash paid for acquired company			$ 31,000
Cash received for acquired entity		1,500	1,500
Future cash payments		$ 1,100	1,100
Combined purchase price of acquisitions			36,000
Common stock paid for acquired company			3,400
Previously-held interest in an equity-method investee			$ 200
Minimum [Member]
Business Acquisition [Line Items]
Useful life			2 years
Maximum [Member]
Business Acquisition [Line Items]
Useful life			5 years