Leases Supplemental cash flow information realted to leases (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018
Cash Flow, Operating Activities, Lessee [Abstract]
Operating cash flows from operating leases	$ (12,524)
Operating cash flows from finance leases	(91)
Cash Flow, Financing Activities, Lessee [Abstract]
Financing cash flows from finance leases	(1,061)	$ (664)
Lease, Cost [Abstract]
Right-of-use asset obtained in exchange for lease obligations, operating leases	$ 52,889