Income Taxes Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 29, 2018	Dec. 30, 2017
Deferred tax assets:
Inventories	$ 4,128	$ 3,146
Retirement benefits	1,718	2,200
State net operating losses	4,142	4,196
Federal net operating losses	4,560	3,204
State tax credit carryforwards	1,688	1,963
Federal tax credit carryforwards	3,721	3,365
Allowances for bad debts, claims and discounts	2,199	2,373
Other	5,646	3,649
Total deferred tax assets	27,802	24,096
Valuation allowance	(16,993)	(12,994)
Net deferred tax assets	10,809	11,102
Deferred tax liabilities:
Property, plant and equipment	11,377	12,207
Total deferred tax liabilities	11,377	12,207
Net deferred tax liability	$ (568)	$ (1,105)