Retirement Benefit Plans Defined Contribution Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Jan. 01, 2017	Jan. 03, 2016
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	75.00%
Defined Contribution Plan, Employer Matching Contribution, Percent	4.00%
Defined Contribution Plan, Cost Recognized	$ 4,704	$ 5,177	$ 6,124

The amount of the cost recognized during the period for defined contribution plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration