Note 6 - Employee Stock Benefit Plans - Stock Options Outstanding and Exercisable (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Number Outstanding (in shares)	472	1,641	1,965	2,435
Options Outstanding, Weighted Average Remaining Life (Year)	4 years 182 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.20	$ 10.79	$ 11.25	$ 11.67
Options Exercisable (in shares)	469	1,537	1,673
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 10.20	$ 10.85	$ 11.47
Range 1 [Member]
Range of Exercise Prices, Lower (in dollars per share)	7.32
Range of Exercise Prices, Upper (in dollars per share)	$ 9.44
Number Outstanding (in shares)	248
Options Outstanding, Weighted Average Remaining Life (Year)	4 years 255 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.16
Options Exercisable (in shares)	248
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.16
Range 2 [Member]
Range of Exercise Prices, Lower (in dollars per share)	9.45
Range of Exercise Prices, Upper (in dollars per share)	$ 10.54
Number Outstanding (in shares)	26
Options Outstanding, Weighted Average Remaining Life (Year)	4 years 292 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 10.41
Options Exercisable (in shares)	26
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 10.41
Range 3 [Member]
Range of Exercise Prices, Lower (in dollars per share)	10.55
Range of Exercise Prices, Upper (in dollars per share)	$ 17.67
Number Outstanding (in shares)	198
Options Outstanding, Weighted Average Remaining Life (Year)	4 years 73 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.48
Options Exercisable (in shares)	195
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 11.49