Leases (Narrative) (Details) - USD ($) $ in Thousands	Mar. 30, 2019	Dec. 29, 2018
Operating Leased Assets [Line Items]
Operating lease right-to-use	$ 193,834	$ 0
Operating lease liability	$ 202,837
Percentage of facilities under operating lease		53.00%
Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	20 years
Minimum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	5 years
Accounting Standards Update 2016-02 [Member]
Operating Leased Assets [Line Items]
Operating lease right-to-use	$ 202,000
Operating lease liability	$ 211,000