Other Long Term Liabilities (Details) - USD ($) $ in Thousands	Jun. 28, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Finance lease obligations	$ 6,764	$ 7,275
Accrued pension liabilities	2,939	3,758
Accrued contingent considerations	7,436	3,376
Other	3,661	2,778
Total	$ 20,800	$ 17,187