Revenue Recognition Effect of Adopting ASC 606 (Details) - Cumulative Effect, Period of Adoption, Adjustment - USD ($) $ in Thousands		Dec. 29, 2018	Dec. 31, 2017
Effect of Adopting ASC 606 [Line Items]
Adoption of ASU		$ (100)	$ 1,100
Accounting Standards Update 2014-09
Effect of Adopting ASC 606 [Line Items]
Adoption of ASU	[1]		$ (4,405)

[1] As of December 31, 2017, the company adopted ASU No. 2014-09, Revenue from Contracts with Customers (ASC 606) using the modified retrospective method to contracts that were not completed as of December 30, 2017. The adoption of this guidance resulted in the recognition of $(4.4) million as an adjustment to the opening balance of retained earnings.