Condensed Consolidated Statement of Changes in Stockholders' Equity - Unaudited - USD ($) $ in Thousands	Total	Common Stock	Additional Paid In Capital	Treasury Stock	Retained Earnings	Accumulated other Comprehensive Loss
Beginning balance (in shares) at Dec. 26, 2017		20,309,341
Beginning balance at Dec. 26, 2017	$ 189,087	$ 24	$ 147,503	$ (67,823)	$ 109,383	$ 0
Net loss	(1,162)				(1,162)
Other comprehensive income (loss), net of tax	0
Share-based compensation costs	2,098		2,098
Stock option exercises (in shares)		4,000
Stock option exercises	52		52
Shares issued under stock compensation plan, net of shares withheld for tax effects (in shares)		69,481
Shares issued under stock compensation plan, net of shares withheld for tax effects	(175)		(175)
Ending balance (in shares) at Jun. 26, 2018		20,382,822
Ending balance at Jun. 26, 2018	190,199	$ 24	149,478	(67,823)	108,520	0
Beginning balance (in shares) at Mar. 27, 2018		20,342,589
Beginning balance at Mar. 27, 2018	190,764	$ 24	148,481	(67,823)	110,082	0
Net loss	(1,562)				(1,562)
Other comprehensive income (loss), net of tax	0
Share-based compensation costs	1,071		1,071
Shares issued under stock compensation plan, net of shares withheld for tax effects (in shares)		40,233
Shares issued under stock compensation plan, net of shares withheld for tax effects	(74)		(74)
Ending balance (in shares) at Jun. 26, 2018		20,382,822
Ending balance at Jun. 26, 2018	190,199	$ 24	149,478	(67,823)	108,520	0
Beginning balance (in shares) at Dec. 25, 2018		33,321,795
Beginning balance at Dec. 25, 2018	213,582	$ 37	248,618	(67,823)	33,379	(629)
Net loss	(24,725)				(24,725)
Other comprehensive income (loss), net of tax	(700)					(700)
Share-based compensation costs	$ 2,221		2,221
Stock option exercises (in shares)	0
Shares issued under stock compensation plan, net of shares withheld for tax effects (in shares)		100,520
Shares issued under stock compensation plan, net of shares withheld for tax effects	$ (192)		(192)
Ending balance (in shares) at Jun. 25, 2019		33,422,315
Ending balance at Jun. 25, 2019	198,916	$ 37	250,647	(67,823)	17,384	(1,329)
Beginning balance (in shares) at Mar. 26, 2019		33,378,025
Beginning balance at Mar. 26, 2019	204,316	$ 37	249,650	(67,823)	23,782	(1,330)
Net loss	(6,398)				(6,398)
Other comprehensive income (loss), net of tax	1					1
Share-based compensation costs	1,010		1,010
Shares issued under stock compensation plan, net of shares withheld for tax effects (in shares)		44,290
Shares issued under stock compensation plan, net of shares withheld for tax effects	(13)		(13)
Ending balance (in shares) at Jun. 25, 2019		33,422,315
Ending balance at Jun. 25, 2019	$ 198,916	$ 37	$ 250,647	$ (67,823)	$ 17,384	$ (1,329)