Income Taxes - Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019
Income Taxes
Balance at the beginning of the period	$ 1,579,000	$ 2,023,000
Additions for tax positions of prior years	60,000	179,000
Reductions for tax positions of prior years	(426,000)	(623,000)
Reductions for lapse of statute of limitations	(183,000)
Balance at the end of the period	1,030,000	1,579,000
Interest expense (benefit) included in income tax expense	18,000	11,000
Income tax expense, accrued interest and penalties	$ 136,000	$ 154,000