Accumulated Other Comprehensive Items - Reclassification Out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Other expense, net	$ (32)	$ (99)
Interest expense	(2,459)	(3,504)
Cost of revenues	(90,804)	(100,801)
Total (expense) income before income taxes	17,215	15,028
Income tax benefit (provision)	(4,559)	(3,963)
Net Income	12,656	11,065
Reclassification out of Accumulated Other Comprehensive Items
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Net Income	64	3
Reclassification out of Accumulated Other Comprehensive Items | Pension and Other Post-retirement Plans [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Total (expense) income before income taxes	(17)	(16)
Income tax benefit (provision)	124	4
Net Income	107	(12)
Reclassification out of Accumulated Other Comprehensive Items | Recognized net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Other expense, net	(15)	(16)
Reclassification out of Accumulated Other Comprehensive Items | Amortization of prior service cost
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Other expense, net	(2)	0
Reclassification out of Accumulated Other Comprehensive Items | Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Total (expense) income before income taxes	(57)	20
Income tax benefit (provision)	14	(5)
Net Income	(43)	15
Reclassification out of Accumulated Other Comprehensive Items | Cash Flow Hedges | Interest rate swap agreements
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Interest expense	(34)	20
Reclassification out of Accumulated Other Comprehensive Items | Cash Flow Hedges | Forward currency-exchange contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Items [Line Items]
Cost of revenues	$ (23)	$ 0