Acquisition Activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Acquisition of business, net of cash acquired	$ 12,072	$ 0
UltraSource [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Purchase price of businesses	13,372
Finite-lived Intangible Assets Acquired	6,500
Goodwill related to acquisitions	$ 4,003
Business Acquisition, Name of Acquired Entity	UltraSource, Inc.
Business Acquisition, Effective Date of Acquisition	Feb. 08, 2018