Share-based Compensation, ASU 2016-09 (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 26, 2017	Dec. 27, 2016
ASU 2016-09 Compensation-Stock Compensation
ASU 2016-09
Cumulative effect on retained earnings	$ (0.1)	$ 0.0

Amount of the cumulative effect on retained earnings net of related income tax effect.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22663-107794

Name:	us-gaap_CumulativeEffectOnRetainedEarningsNetOfTax1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration