NET INCOME PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015
Earnings Per Share [Abstract]
Net income for basic and diluted per share calculation	$ 12,025	$ 8,960	$ 40,761	$ 30,183
Weighted average shares outstanding - basic (in shares)	15,048	15,342	15,002	15,327
Effect of potentially dilutive securities (in shares)	187	190	180	180
Weighted average common shares outstanding - diluted (in shares)	15,235	15,532	15,182	15,507
Basic net income per common share (in dollars per share)	$ 0.80	$ 0.58	$ 2.72	$ 1.97
Diluted net income per common share (in dollars per share)	$ 0.79	$ 0.58	$ 2.68	$ 1.95