Significant Accounting Policies - Basis of Presentation and Principles of Consolidation (Details)	12 Months Ended
	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Significant Accounting Policies
Length of fiscal year	364 days	364 days	364 days
Low end of range
Significant Accounting Policies
Length of fiscal year	364 days
High end of range
Significant Accounting Policies
Length of fiscal year	371 days