CONSOLIDATED CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Jul. 01, 2017	Dec. 31, 2016	Jun. 25, 2016
SHAREHOLDERS' EQUITY:
Preferred stock, no par value (in dollars per share)	$ 0	$ 0	$ 0
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0	0
Preferred stock, shares outstanding (in shares)	0	0	0
Common stock, no par value (in dollars per share)	$ 0	$ 0	$ 0
Common stock, shares authorized (in shares)	80,000,000	80,000,000	80,000,000
Common stock, shares issued (in shares)	20,421,775	20,342,069	20,307,463
Common stock, shares outstanding (in shares)	20,421,775	20,342,069	20,307,463