Note 12 - Shareholders' Equity - Performance Shares Outstanding (Details) - Performance Shares [Member]	12 Months Ended
	Dec. 30, 2018 $ / shares shares
Outstanding at January 1, 2018 (in shares) | shares	669,500
Outstanding at January 1, 2018 (in dollars per share) | $ / shares	$ 17.51
Granted (in shares) | shares	261,000
Granted (in dollars per share) | $ / shares	$ 25.69
Vested (in shares) | shares	134,000
Vested (in dollars per share) | $ / shares	$ 17.72
Forfeited or cancelled (in shares) | shares	37,000
Forfeited or cancelled (in dollars per share) | $ / shares	$ 19.93
Outstanding at December 30, 2018 (in shares) | shares	759,500
Outstanding at December 30, 2018 (in dollars per share) | $ / shares	$ 20.17