Computation of Basic and Diluted Earnings per Common Share (Parenthetical) (Details) - shares	6 Months Ended
Jun. 28, 2019	Jun. 29, 2018
EPS Performance-based Restricted Stock Units
Computation Of Earnings Per Share [Line Items]
Contingently issuable shares excluded from calculation of denominator	45,252	53,968
Laser Quantum \| Restricted Stock
Computation Of Earnings Per Share [Line Items]
Contingently issuable shares excluded from calculation of denominator	213,219

Number of shares of equity interests issued or issuable to acquire entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration