Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 27, 2020	Dec. 28, 2019
Accumulated depreciation	$ 106,232	$ 125,990
Preferred stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value per share (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	135,147,000	133,883,000
Common stock, shares outstanding (in shares)	135,147,000	133,883,000