New Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Prior Period Reclassification Adjustment	$ 0	$ 0	$ 595

The amount of a reclassification adjustment made to prior period financial statement amounts.

No definition available.

Name:	us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration