Income Taxes - Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 25, 2016	Dec. 27, 2015
Income Taxes
Balance at the beginning of the period	$ 5,670,000	$ 4,328,000
Additions for tax positions of current year	126,000	529,000
Additions for tax positions of prior years	183,000	2,005,000
Reductions for lapse of statute of limitations	(1,152,000)	(1,192,000)
Balance at the end of the period	4,827,000	5,670,000
Interest benefit included in income tax expense	278,000	217,000
Income tax expense, accrued interest and penalties	$ 544,000	$ 825,000