Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 673	$ 4,171	$ 1,591	$ 2,600	$ 9,484	$ 4,655	$ 3,823	$ 2,115	$ 9,035	$ 20,077	$ 25,261
Pension Adjustments:
Amortization of actuarial losses included in net income, net of tax benefit of $173, $302, and $283 for 2018, 2017, and 2016, respectively									570	508	479
Actuarial losses arising during the period, net of tax benefit of $302, $194, and $413 for 2018, 2017, and 2016, respectively									(899)	(304)	(650)
Change in net unrealized gains (losses) on cash flow hedges, net of tax expense (benefit) of $121, $(145), and $(180) for 2018, 2017, and 2016, respectively									407	(242)	(305)
Other Comprehensive (Loss) Income, Net of Tax									78	(38)	(476)
Comprehensive Income, Net of Tax									$ 9,113	$ 20,039	$ 24,785